Properties of coniferous wood. Educational research work "Diseases of tree species and assessment of the ecological state of the forest"

Stem pests make up a large environmental group insects that feed on the tissues of tree trunks; in the phase, the larvae lead a hidden lifestyle. These include insects mainly from the order of coleoptera: the families of bark beetles, barbel beetles, golden beetles, weevils, etc., as well as horn-tails (order Hymenoptera), woodworms and glassworms (order Lepidoptera).

Stem pests have varying degrees of activity. Some of them attack trees without visible signs of weakening, others - only very weakened, almost lost their vital functions, or fallen trees. In this regard, even in the last century, a dispute arose about the ability of insects of this group to populate healthy trees and about the advisability of naming them "secondary pests". It is now generally accepted that the activity of stem pests depends on the environmental conditions in which they live.

Stem pests belonging to different families differ greatly in their structure and biology. Therefore, each family is given a separate characteristic. All stem pests are united by a similar ecology and, above all, their relationship with tree species.

Populating trees

Most stem pests are oligophagous and occur on several related tree species. Within the preferred tree species, the process of selecting and populating trees with stem pests is determined by the successive action of attractants, which have a primary attraction, and pheromones, which cause a secondary attraction (see Chapter IV). When flying, insects are guided by the smell of trees suitable for settling. Such trees usually enhance the production of attractants due to changes in their physiological state.

After the settlement of the first insects on trees of the corresponding physiological state, they begin to increase the release of pheromones, which sharply increases the attractiveness of the tree. These insects are called "pioneers". The more of them, the stronger the effect of the released pheromones and the faster the further colonization and development of the tree by pests occurs.

A change in the physiological state of trees is usually associated with a violation of their water regime. At the same time, in conifers, the pressure of the resin decreases, which mechanically and toxicly protects trees from the attack of stem pests, the pressure of the bast layer of the bark changes, and in deciduous trees, the amount of sap released. In general, we can say that weakened trees undergo profound changes in many physiological parameters. At the same time, many trees, mobilizing their internal reserves, restore the disturbed normal state and successfully repel the attacks of the "first settlers". So, after a ground fire in a pine forest, you can often see resin funnels and attempts to embed pine beetles on the bark of trees. These are traces of a failed insect attack on a tree. In deciduous species, overgrowth of the initial colonies of barbel and golden beetles is often observed as a result of intense callus.

Trees inhabited by stem pests die off in different ways. This is due to the nature of the weakening of the tree and the sequence of their settlement. There are two main types of tree weakening: root and apical.

All reasons that weaken the root systems of trees (ground fires, drought, changes in the level of groundwater, soil compaction, root sponge, honey fungus, etc.) lead to drying out according to the root type. In this case, drying begins from the lower part of the trunk, which is the first to be colonized by pests. The crown at this time is often still completely green and the upper part of the tree is free from pests. A characteristic dead wood with a green crown is formed.

Under the influence of damage from resin crayfish, needle-gnawing insects, gases, etc., the trees begin to dry out in the crown area. The crown may already be inhabited by insects, while the lower part of the tree is still viable. This type of attenuation is called vertex attenuation.

Along with these two types of weakening of trees in the centers of stem pests, there is a type of simultaneous weakening of the entire tree, when it is colonized by insects all over the trunk at once. Finally, certain parts of the tree may die off in places of damage (burns, burns, frost holes, cancerous wounds, etc.) and colonize them with pests. This type is called local withering away.

Ecological groups of stem pests are determined by the nature of the death of trees in the foci and the time of their weakening. Depending on the time of weakening for each type of withering away, there are more subtypes: spring and summer. The established types of withering away made it possible for A.I. Ilyinsky (1931, 1958) and his students to develop generalized schemes for the formation of ecological groups of stem pests, facilitating work on forest pathological examinations, supervision and design of control measures.

Areas of mass breeding

In the case of mass colonization of trees with stem pests, foci are formed in forests. Conditionally, weakened stands are referred to as foci, where there are more than 10% of trees inhabited by pests.

In weakened plantations, insects find an excess of food at the expense of the trees that have lost their vitality, on which they settle. As a result, there is a rapid growth in the population of stem pests. As the number of pests increases, there are fewer and fewer unoccupied trees in the plantation. When all weakened trees are colonized, the density of the pest settling on the tree begins to increase. An increase in density first contributes to better survival of pests, and then leads to the development of competition between them, the massive appearance of entomophages and diseases.

Centers of stem pests in plantations are formed as a result of drought, winter frosts, a sharp violation of the groundwater level or flooding, erosion, massive damage to needles and leaf-eating insects, vertebrates, fires, lightning, wind and snow, smoke and gases, fungal diseases as a result violations of sanitary rules in forests, thinning of plantations, soil compaction and damage to root systems during grazing, etc.

Each focus in its development goes through several phases. Usually, foci are distinguished between arising, active and fading. They differ in the ratio of trees of different categories and the state of populations of stem pests.

Weakened trees predominate in the emerging foci, some of which are inhabited by pests. Existing outbreaks are characterized by the fact that trees, freshly populated by pests, dominate over exhausted ones (old dead wood). In decaying foci, the largest number of dead trees (or remaining stumps) are already exhausted by insects, and very few weakened and freshly populated ones.

The outbreak can last for a different number of years. It depends on the reasons under the influence of which it arose, and on the weather conditions. There are temporary foci, or episodic, acting from one to several years, and chronic foci, acting for many years. The latter are most often confined to places of development of fungal diseases and stands growing in unfavorable conditions.

The lesions differ sharply from each other, depending on the causes that cause them. Even in plantations with the same forest growth conditions and taxation indicators, foci of different types of stem pests can form and develop unequally.

The most common types of lesions are discussed below.

Gary. In the forests, temporary centers are especially common, arising under the influence of forest fires.

Population of burnt places with stem pests depends on the time of the fire, the strength of the fire and the size of the fire, the age of the plantations damaged by the fire, as well as on the forest growing conditions. The sanitary condition of the burned areas, the stock of pests in the surrounding plantations and weather conditions also have a great influence on the spread of stem pests.

According to the time of occurrence of a fire, burns are divided into spring (April - May), summer (June - July) and autumn (August). Most often, there are spring burns, which are populated by pests in the year of fire and pose the greatest danger to insect reproduction. August fires are usually not populated by pests in the year of fire.

Very strong changes are taking place on the burned-out areas. Trees weakened by fire dry out, damaged by pests and die. The response of different tree species to fire damage is different. Trees with thick bark, deep root system, high crown and little resinousness suffer less from fire. Pine, larch, oak are fire-resistant species, spruce and fir suffer the most from fire, Siberian cedar occupies an intermediate place.

One of the most important signs characterizing the state of sustainability of the main forest stands damaged by fire is the height of soot on the trees. With an average height of soot up to 2.5 m, mortality from the stand does not exceed 25% in terms of the stock, with 2.5-4.4 m - 50, and with 4.5 - 6.5 m - 70%. Carbon deposits of more than 6.5 m are accompanied by a loss of over 70% of the reserve. The most reliable sign is the state of the crown (Galasyeva, 1976).

A runaway grassland fire is not life-threatening for the plantation. Only individual trees lose their protective properties, become unviable and are colonized by pests. On such burned-out areas, five years after the fire, the total mortality in the stock will be no more than 5%, and pests are not formed.

A sustained ground fire in middle-aged and ripe plantings causes a burn of the root paws and root collar of trees, drying out of the bast and resinification of water-conducting vessels, leading to a disruption of the water supply to the crown. The resin-excreting reaction falls primarily in the lower part of the trees, and many of them are colonized by pests in the first two or three years. On small burned-out areas, up to 5 hectares in size, the maximum population of trees with stem pests occurs in the first or second year after the fire, on large fires - in the third or fourth, and sometimes even in the fifth year. The order of settlement and the duration of the stay of stem pests on burned-out areas depend on the time of their formation, forest conditions and geographical location.

The effect of a fire on the intensity of tree mortality on burnt-out areas and their infestation with stem pests increases with the growth of clutter in the plantings. At the same time, the completeness and shape of the stands are of great importance. The loss decreases with an increase in the density of stands. The lower temperature and higher air humidity, as well as the calmness in full stands, weaken the intensity of the fire. In rare stands, due to different phytoclimatic conditions, the environment for the development of fires is more favorable. In addition, in rare stands, the number of the most dangerous stem pests is higher.

An indiscriminate fire, burning roots, trunks, branches, leads to the fall of part of the trees and their significant charring and therefore does not significantly affect the reproduction of stem pests.

After the inflow of pests to the burnt-out, the reverse process begins - their outflow and dispersion in the surrounding plantations, in which curtain foci of bark beetles appear (in coniferous forests) and goldfish (in deciduous forests), and then increased tree mortality begins.

To prevent this phenomenon, the burnt-out area should be used as a trapping area, and pests should be eliminated faster and more completely, preventing them from scattering into the surrounding plantings.

Fungal diseases. The reproduction of stem pests is closely related to foci of fungal diseases. The immediate cause of tree death in the foci of root sponge and honeydew is usually stem pests. The dying off of trees is of the butt type. In the forest zone, the spring subtype of settlement prevails, pine beetles dominate. In the forest-steppe and steppe zones, the weakening of a diseased tree occurs due to increased transpiration, which cannot be satisfied by the work of the damaged root system. Therefore, the summer subtype of butt settlement appears more often, starting with the settlement of the blue pine goldfish and the six-toothed bark beetle-stenographer. Then they are joined by a black pine barbel and trunk resin.

In spruce plantations infected with root rot, mass reproduction of stem pests is observed only during drought years. The spring subgroup of species predominates - mainly the typographer; he is accompanied by a double and an engraver. The role of the summer subgroup (fluffy polygraph, spruce resin, barbel) depends on the composition, age and completeness of plantings and is usually small in number. Trees in spruce stands most often die off according to the stem type, there is a transition from the butt through the stem to the summit.

Resin cancer most often causes local weakening and death of parts and tissues of the tree, due to the development of a cancerous wound in the crown of the tree. Stem pests inhabit the part of the tree located above the cancerous wound. The top dies off, but the tree continues for more long time live. If a cancerous wound is located under the crown, the weakening and death of the tree occurs according to the apical type. The apical bark beetle is the first to attack such trees, quickly reaching a very high number due to reproduction on branches, which, as a rule, are not removed during sanitary felling. Together with it, the small pine bark beetle, the four-toothed bark beetle, smolens, the barbel of pine tops, etc., settle.

In deciduous plantations, there is a close relationship between the spread of a number of vascular and cancerous diseases of tree species and the reproduction of stem pests. So, foci of Dutch disease are almost always places of mass breeding of elm sapwood.

Droughts. After severe droughts, foci of narrow-bodied goldsmiths appear in oak forests, typographer's bark beetle in spruce forests, Altai barbel, and larch goldsmiths in larch forests.

The emergence of foci of stem pests in plantations damaged by pine and leaf-gnawing pests was indicated earlier (see Chapter VIII). This usually happens in coniferous stands, especially in the breeding grounds of the Siberian silkworm. Black longhorns follow the traces of his injuries. The most dangerous is the black fir barbel. Settling on trees devoid of needles, it rapidly increases in numbers. The hatching adults fly to neighboring plantations, where, in the process of additional feeding, they weaken the trees and thereby prepare the food base for the next generation.

Anthropogenic influences. The systematic renewal of the plantation with shoots leads to its degeneration. Any such planting is weakened and conditions are created in it for the reproduction of stem pests.

The coppice stands are incomparably more infested with the large oak barbel than the seed plantations. The unsatisfactory state of hornbeam plantations and the appearance of foci of narrow-bodied hornbeam and hornbeam sapwood in them is also associated with their coppice origin.

Thinning of stands below the normal density for a given habitat, an increase in the perimeter of forest edges, and strip cuttings lead to an increase in illumination, disruption of the normal forest environment and a weakening of the stand. In such stands, as a rule, breeding centers of many stem pests appear. In deciduous stands, the pioneers are gold beetles, in spruce stands - bark beetles and barbel beetles, in pine stands - blue pine beetle, apical bark beetle and stenographer, black pine barbel, in larch stands - oblong bark beetle.

Long-term foci often also arise in plantations that are biologically unstable, growing in poor forest conditions, or when the type of crops, tree species and their mixture do not correspond to these conditions.

In weakened plantations, stem pests find an excess of food due to the trees that have lost their vitality, on which they settle. As a result, there is a rapid growth in numbers. As the number of pests increases, unoccupied weakened trees become less and less. When they are all populated, the density of pests on the tree begins to increase. At the same time, at first, the number of the young generation increases, and then, with a high and very high density of tree population, it begins to decline. At this time, the length of the uterine passages decreases, the number of eggs laid in them decreases, and the mortality of the larvae increases. The density of pests on a tree also affects the effectiveness of their enemies.

Control measures

The fight against stem pests consists of the supervision of their mass appearance and distribution, the implementation of sanitary rules and chemical control measures.

Supervision

Supervision is organized in all forestry enterprises and is carried out by groups of stem pests. In accordance with general principles, special surveillance is carried out in the form of reconnaissance - in order to detect mass reproduction and the area of ​​foci of stem pests, and detailed - to assess the dynamics of the number of insects and their threat to plantations.

Detailed supervision is carried out by methods of forest pathological examination, and in chronic foci it is supplemented by annual observations on stationary test plots, which are laid for 10 years. With detailed supervision, the root cause of the weakening of plantings is specified, their condition, species composition and main groups of stem pests are determined, and the indicators of their population dynamics are recorded. Based on the results of the forecast obtained, pest control measures are prescribed.

With detailed supervision on sample plots, trees are counted according to categories of state (healthy, weakened, strongly weakened, drying out, fresh and old dead wood), then models are taken from the number of freshly populated trees and the species composition of stem pests, population density and breeding factor for leading species. It also takes into account the state of the population, the presence of entomophages and diseases.

Based on surveillance data, combined with an analysis of meteorological indicators and an assessment of the sanitary state of plantings, a forecast is made and, on its basis, pest control measures are designed. The threat of the forthcoming colonization of plantations with stem pests is determined by the ratio of trees of different categories (mainly populated to unoccupied, but strongly weakened) and the multiplication factor.

Sanitary rules

are aimed at preventing mass reproduction of pests and diseases in forests through systematic sanitary felling of forests and maintaining the established regime - cleaning of felling residues and debarking of wood.

In the forest, it is necessary to carry out a systematic cleaning of dead forest and dead wood, to choose freshly populated with pests and drying out trees, if necessary, to carry out selective and clear sanitary felling.In the places of logging, timely cleaning of felling sites, removal, debarking or chemical protection of forest products, debarking or chemical treatment of coniferous stumps is necessary rocks.

When assigning forest sites for sanitary felling, one should pay attention to the fact that excessive thinning of plantings leads to a loss of tree resistance and to their death. It is necessary to strive to ensure that after selective sanitary felling, the stand density is not less than 0.7, and in rare stands - 0.6. For clear sanitary felling, areas are allotted where it is infected with stem pests and more than 40% of the trees dry out. The exception is the previously thinned out, already disturbed plantings.

The plantations planned for clear sanitary felling must be preliminarily inspected by the commission (it is appointed by the director of the enterprise) and all documentation must be drawn up in accordance with the requirements of the "Sanitary Rules in the Forests of the USSR".

One of the main tasks of forest thinning is to improve the sanitary state of the forest and increase the resistance of forest stands against pests and diseases. Therefore, when thinning the forest, first of all, trees infected with stem pests are cut down, dry-topped trees that have mechanical damage and are prone to colonization by pests, physiologically decrepit.

Final felling planning

When planning forest felling, one should strive to squeeze the perimeter of cutting areas as much as possible, since curtain foci of stem pests most often appear along the edges, avoid cross-strip and en-echelon felling, take into account the direction of the prevailing wind, first of all, develop burnt areas, windbreaks, windblows and other categories of stem foci described above. pests and stands where they can occur.

Among the active measures for the control of stem pests in forestry, the following are used: sampling of freshly populated trees, laying out trapping trees and chemical insect control.

Selection of freshly populated trees

Sampling of freshly populated trees is carried out systematically in all plantations, which are threatened by the risk of breeding of stem pests. It cannot be equated with conventional selective sanitary felling, which involves the removal of dead and faded trees.

On the trunks of freshly populated trees to be cut down, the forest guard puts marks, which are checked by specialists: a technician, forester or forest pathologist. Trees inhabited by stem pests are recognized by one of the following signs: the presence of drill meal at the base of the trunks, by resin funnels and small holes - insect entry holes - on the trunks, by abundant streaks of resin along the trunk, swelling on the trunks filled with blackish or brown protruding on the surface with liquid (badges), incisions made by barbel to lay eggs, along thinned foliage, sometimes on a yellowed crown, damaged roots, dark cambium. In doubtful cases, a thorough examination is necessary with the opening of the area of ​​the bark, under which the passages of insects should be.

Trees that are freshly populated with stem pests should be cut down while the larvae are under the bark. It is impossible to stretch the felling time, since the emerging young beetles can remain on the ground and crawl away when felling and skinning trees. Felled trees must be immediately lumped or treated with pesticides, which is much easier and more cost-effective.

Laying out trapping trees

Laying is advisable only if sanitary rules are observed and at the same time sampling of freshly populated trees. When laying out trapping trees, it is necessary to take into account the ecology of the corresponding types of stem pests, the geographical location of plantings, their forest growing conditions, sanitary conditions, the direction of the economy, the number of bark beetles. Trapping trees must be laid out in time, debarked and developed in time, otherwise they will turn into a breeding ground for stem pests.

The number of trapping trees in one or another part of the forest should correspond to the number of trees inhabited by stem pests last year. The number of stem pests is determined on model trees when examining foci. Model trees are taken from the number of freshly populated trees and the species composition of stem pests is determined on them, and the number of leading species is determined by the number of uterine passages (breeding chambers) in bark beetles and by the number of larvae (or their disappearance into the wood) in longhorn beetles, golden beetles and elephants. With a high number of pests of trapping trees, there should be no more than the total number of populated trees, with an average - no more than half, with a weak one - no more than a quarter. If it is impossible to determine the number of stem pests, trapping trees are laid out on the basis of materials about the release of last year's dead (bark beetle) forest.

There are several ways to lay out trapping trees: by leaving them standing, artificially weakening or cutting down and laying out whole trees with a crown, whips or assortments. For greater capacity, the trees are laid on lining 15 - 20 cm thick. It is better to lay out the trapping trees in groups, and not scattered throughout the plantation. They need to start laying out a month before the start of flight of bark beetles: at the end of February - March against the first generation and in June - July - against the second.

Debarking of trapping trees should be carried out after hatching of the bulk of the larvae, but it is more expedient to replace it by chemical treatment with a 16% concentrate of the emulsion of the gamma isomer of hexachlorane. Processing of trapping trees should be carried out before the start of flight of those stem pests that are being controlled in the area. In the southern regions, repeated chemical treatment of trapping trees is required in 1.5 - 2 months. If the trapping trees have not been pre-treated, they can be sprayed during the period of mass pupation and the appearance of young beetles, but the effectiveness of the fight decreases.

Chemical fight

Chemical control of stem pests consists in protecting the trunks of weakened trees during the flight of pests, destroying them during additional feeding, processing freshly populated and trapping trees, forest products in the forest and in warehouses.

The chemical protection of weakened trees consists in treating them with pesticides before and during the flight of the main bark beetles, barbel beetles and golden beetles.

The best results are achieved when tree trunks are sprayed with 3% working fluids of a 16% concentrate of a mineral oil emulsion of the gamma isomer of hexachlorane and a 4% solution of technical hexachlorane in diesel fuel. When protecting tree trunks chemically, the nature of the bark must be taken into account. When processing thick and transitional bark, it is advisable to reduce the strength of the applied working solutions (up to 2 - 4%), but to increase the fluid consumption, since the cracks and cracks in the bark on such trees are deeper. The flow rate in this case should be 0.6 - 2 liters per 1 m2 of bark surface. When processing the smooth bark of trunks and branches, the consumption of the working solution is reduced to 0.2 - 0.4 liters per 1 m2, since it unproductively flows from its surface; the concentration of the solution must be increased to 6-10%.

The success of the chemical treatment of weakened trees that have been attacked by stem pests depends to a large extent on adherence to the terms of protection. Therefore, it is very important to conduct systematic phenological observations and to know well the time of appearance major species pests found in the area of ​​protected objects. You should also pay attention to what part of the tree trunk each of these species populates. If the butt part of the trunk is populated in the area of ​​the thick bark, you can limit yourself to processing only this part. It is much more difficult to protect trees infested by pests from the tops. The treatment of crowns with the same drugs often gives an inferior result, but it is possible. It can be carried out to combat elm sapwood, large pine bark beetle, black barbel, etc.

Along with protecting weakened trees in valuable plantations by chemical means, beetles can be destroyed on freshly populated trees before they leave and in wintering places. Freshly populated trees are felled and, instead of debarking, chemically treated in the same way as weakened trees standing at the root. At the same time, the toxic chemical flows into the cracks in the bark, the entrance holes of insects and, seeping under the bark, destroys the larvae, pupae and hatching young beetles. The surviving beetles, when flying out, come into contact with the poison on the surface of the bark and also die.

Fighting in wintering places is carried out by spraying the soil surface, root paws and bases of tree trunks, where many bark beetles and elephants winter (liquid consumption 0.25 - 0.5 liters per 1 m2).

The above chemical control measures have been successfully applied against latent-stem insects that spend part of their life or all their lives under the bark of trees and only for some time shallowly in the wood (bark beetles, golden beetles, part of the barbel, elephants). The corrosive chemical method has not yet been developed against the vitreous and arboreal living in wood. Possible methods of control are outlined when describing these types of pests.

Overview of selected species

Coleoptera (Coleoptera)

Bark beetles (Scolytidae)

Bark beetles form a relatively small family of beetles, whose life is closely related to the tree. They have a short cylindrical body with a small head. The largest bark beetle of the 300 species found in the USSR is about 9 mm long, and the smallest is 1 mm. The color of the beetles is usually brown, brown or black. The body is covered with strong leathery elytra, under which there are well-developed membranous wings, with the help of which the beetles fly. Eggs of bark beetles are white, small. The larvae are fleshy, legless, slightly curved, with a clearly visible dark head, glabrous or slightly hairy. Pupae are white.

According to their external features, bark beetles are divided into three sharply different groups: bark beetles, sapwood and true bark beetles (Fig. 93).

In bark beetles, the posterior end of the body is convex and rounded, as is typical for most other beetles.

The sapwoods differ in the shape of the abdomen, which is cut obliquely from the hind legs to the apex of the elytra, due to which the posterior end of the body resembles a chisel.

Real bark beetles have a deep depression (wheelbarrow) at the rear end of the body, surrounded by teeth and forming a kind of wheelbarrow or basket. The number of teeth and their shape are different in different species, but they are constant for each species.

The features of the body structure of bark beetles are closely related to their lifestyle. Bark beetles spend almost their entire life under the bark of tree trunks and branches. There they make moves that have the shape of certain figures. Each species of bark beetle has a course of a certain shape.

The moves are simple and complex. Simple passages consist of one canal, which is gnawed by the female and is called the uterine passage. They are longitudinal and transverse. Complex passages have several channels and are divided into stellate ones with a slope towards the longitudinal and transverse directions and radiant (Fig. 94).

Each species of bark beetle always settles on a certain tree species or several closely related species and occupies a certain part of the tree. So, for example, the large pine bark beetle usually inhabits the tree in its lower part, where the bark is thick, and is very rare on the top of the pine, where the bark is thinner, and the small pine bark beetle, on the contrary, inhabits a tree with a thin bark and does not settle under a thick ...

There is a connection between the shape of the passages, the place of settlement of bark beetles on conifers and the structure of the resinous system. In the lower part of the trunk, where there are fewer resin drifts, bark beetles settle, making longitudinal passages, and in the upper part of the trunk, where there are more resin drifts, there are bark beetles making transverse and stellate passages.

The flight of bark beetles usually begins in spring and lasts until mid-summer. The first (at the end of April) to fly are pine beetles and other bark beetles living on the pine. Then spruce bark beetles and sapwoods appear, living on deciduous species.

Bark beetles create a family during the breeding season. Moreover, some species of bark beetles, usually bark beetles and sapwoods, have a monogamous (monogamous) family consisting of a female and a male, while others, mainly bark beetles proper, have a polygamous (polygamous) family consisting of one male and several females.

In monogamous bark beetles, the female gnaws an oblong inlet on a tree and lays a longitudinal or transverse uterine passage under the bark. On both sides of the passage, the female lays eggs in specially arranged egg chambers, gluing them with a small amount of very small sawdust, compacted and glued together by secretions from the accessory gonads. The larvae hatched from the eggs gnaw the larval passages. They gradually expand as the larvae grow and end in pupal cradles, in which the larvae turn into pupa, and pupae - into adult beetles. The beetles hatch almost white, but gradually acquire their normal color, gnaw through the round flying holes and fly out for additional feeding or for hibernation.

In a polygamous family, the male gnaws the entrance hole. Under the bark, he arranges an irregularly shaped cavity - a breeding chamber, in which several beetles can fit. Females sequentially enter the chamber (from 2 to 12). After mating, each female begins to gnaw through her uterine passage and lay eggs. The uterine passages extend from the mating chamber in different directions.

If the uterine passage is directed up the tree trunk and is against the inlet, drill meal (sawdust) is poured out through the breeding chamber and this hole outward. From the uterine passages directed downward or located at an angle, the drill meal itself cannot spill out. It is thrown out of the course by the male with the help of a wheelbarrow located at the end of the body.

Among the bark beetles, there are species that gnaw through the inlet, ending in an extended short uterine passage, where the female lays eggs in one or several heaps at once (dendroctone bark beetle). The hatched larvae gnaw the joint family larval passage, which is a vast cavity, usually filled with resin. Some bark beetles lay eggs in a bunch at the end of the uterine passage, but the larvae gnaw separate passages in different directions (kryphaly bark beetles). The main types of bark beetle passages are shown in Fig. 94.

The smallest bark beetles (body length 1.2 mm) of the genus Crypturgus are taken into the passages of other bark beetles and from their edges begin to lay their own passages forming a dense network.

Bark beetles living in wood (woody beetles) have their own characteristics. The female usually gnaws the uterine canal perpendicular to the axis of the tree trunk. The feeding canals originate from the uterine canal, from which larval passages begin in some species, while in others, the larvae do not make independent moves and use only those made by the female.

Timber growers have a close relationship with fungi, which are constantly in the intestines of beetles and enter the wood with them. Before laying the eggs, the females carry out a "mushroom sowing" in the wood. The released spores of the fungus fall into favorable conditions of moist wood, immediately germinate and form a mycelium. The larvae feed on the mycelium and, due to this, are fully provided with nitrogenous substances, which allows them not to expend energy on making long passages in the wood.

Bark beetles fly and lay eggs for about a month. The egg phase lasts 10-14 days, the larval phase lasts 15-20 days, and the pupa lasts 10-14 days. Thus, the entire life cycle ends in 1.5 - 2 months, after which a period of additional nutrition begins, which is necessary for the full development of the reproductive system.

For most bark beetles, additional food takes place under the bark of a tree, where they gnaw out short passages of various shapes, called mines. Some species, such as pine bark beetles, gnaw the inner part of young shoots, which, unable to withstand their weight, break off and fall to the ground. A number of sapwoods feed on succulent bast in the forks of twigs, and root veins - on the trunks of young pines.

The cold hardiness of bark beetles is closely related to the nature of their wintering. Those of them, which always have one generation (pine and ash bark beetles), hibernate in the beetle phase at the base of the trunks, trees in short mine passages in the bark or in the forest litter. Due to the snow cover, they are less vulnerable during low temperatures. Young beetles, pupae and larvae hibernating under the bark of trees in their nests have different attitudes towards low temperatures. If such wintering is common for the species, the larvae can withstand temperatures down to -30 ° C, if unusual, then many die already at -15 ° C.

High summer temperatures can also cause high mortality of bark beetle larvae and pupae. Often, under the influence of sunlight in June, the temperature under the bark of spruce rises above the upper thermal threshold of development (usually above 40 ° C) of bark beetles, and their larvae perish in mass.

Bark beetles have varying degrees of activity, however, as a rule, perfectly healthy trees do not populate. Many of them, moreover, are sensitive to ambient light, temperature and humidity conditions, being typical indicators of certain habitats.

In different geographical areas, the number of species of bark beetles and their activity are different. The bark beetle fauna of the Caucasus and the Far East is especially diverse. Many endemic species are found in Central Asia.

Control measures with bark beetles, common to the group of stem pests, are described above.

The greatest distribution and economic value have the following types.

On a pine tree.Great pine bark beetle (Blastophagus piniperda L.)(fig. 95). The beetle is 3.5 - 4.8 mm long, oblong, black-brown, shiny, the elytra are punctured and have two slightly deepened grooves on the sloping part. It flies in late April - May and is the first to populate weakened trees in pine plantations of different ages, especially in burnt-out areas and in foci of root sponge. Females grind under the thick bark of the lower part of the pines from the bottom up a longitudinal single uterine passage from 3 to 23 cm long without a breeding chamber. Moves are imprinted on the sapwood and the edges are heavily tarred. Larval passages are long, wriggling. Young beetles hatching in June - July gnaw out the exit holes and fly away into the crowns of neighboring trees, where they bite into the shoots of the current, less often last year, and eat out the core, as a result of which the shoots break off. One beetle can damage up to seven shoots. In autumn, beetles leave the crown and hibernate at the base of pine trunks, making short passages in the thickness of the bark. Generation is one-year.

Lesser pine bark beetle (Blastophagus minor Hart.). The beetle is 3.4 - 4.0 mm long. It is very similar to the previous species, but the elytra are usually reddish-brown in color and there are no deepened grooves on their sloping part. Beetles fly one to two weeks later than the large bark beetle. Females grind under the thin bark in the upper part of the pines transverse, deeply imprinted on the sapwood uterine passages, which look like a bracket. The length of the uterine passage is from 4 to 32 cm. Short larval passages are directed to both sides of the uterine passage along the tree trunk. Each of them ends with a cradle deep in the sapwood. Young beetles undergo additional feeding in the crowns, gnawing shoots, and hibernate in the forest litter. Generation is one-year.

Both types of pine beetles are shade-loving, found everywhere in a wide variety of stands. The large bark beetle dominates over the small one in more humid forest types. Both are well attracted to trapping trees.

In the Far East, Korean cedar is harmed by the widespread Far Eastern cedar bark beetle(Blastophagus pilifer Spess.), Which resembles the small pine beetle in lifestyle. In the same place, in the mountain forests on the Sayan spruce, another representative of this genus settles - Far Eastern spruce bark beetle(Blastophagus puellus Rt.).

Both species are generated annually. They do not have great economic value, which is how they differ from European species that cause great harm.

Six-toothed bark beetle(Ips sexdentatus Boern.) (Fig. 96). The beetle is 5 - 8 mm long, usually 6 mm, brown, shiny. There is a wheelbarrow at the end of the elytra, with six teeth on each side. It settles in the lower part of the pines under the thick bark. One - three very long (up to 50, and occasionally 70 cm) wide (3 - 4 mm) uterine passages depart from the breeding chamber, sharply imprinted on the sapwood. The larval passages are shorter than the uterine ones, slightly touch the sapwood, greatly expand at the end and end in pupal cradles on the inner surface of the bark.

Widespread in Europe. It is found in the mountains, harms fir and spruce in the Caucasus, and in Siberia and the Far East - cedar. In Yakutia, Altai, and in the European part of the USSR, it is a typical Scots pine pest. Flight usually begins in early May, but high in the mountains and northern regions of Siberia, it is observed only in the first ten days of June and is very extended. The young generation of beetles hatches in 40-50 days. Young beetles immediately begin additional feeding, gnawing short star-shaped passages. Hibernates in forest floor or mine codes under thick bark. Generation is one-year, and in the southern regions - double.

The species is photophilous, xerophilic, inhabits weakened pines in the foci of the root sponge, on burnt-out areas, in sparse plantations, in forests affected by pine-gnawing pests, especially the Siberian silkworm. Inhabits forest products in felling areas, multiplies strongly in areas of selective felling, goes well for trapping trees.

Vertex bark beetle(Ips acuminatus Gyll.) (Fig. 96). Beetle 2.2 - 3.7 mm long, brown, shiny, slightly hairy; there are three prongs on the outstretched wheelbarrow. The flight of beetles takes place in early May. The beetle settles in the upper part of the weakened pines, where it grinds through very characteristic passages. One to eight uterine ducts, 5 to 50 cm long and 2 mm wide, extend from the breeding chamber. The uterine passages are clogged with drill meal, the larval passages are short, rapidly expanding, rare, deeply imprinted on the sapwood. Generation is one-year, and in the south of the USSR it is double. The species is extremely light-loving, often settles on pines infected with resin crayfish, in sparse plantations, especially where tapping was carried out or there was a reproduction of needle-gnawing insects.

Four-pronged engraver(Pityogenes quadridens Hart.). The beetle is 1.5 - 2.3 mm long, brown, the wheelbarrow has four teeth on each side. Inhabits the tops and thick branches of pine trees. In its course and way of life, it resembles the summit bark beetle, but is less active and photophilous. Generation is usually one-year, but it can be double in the south.

Bark beetle(Orthotomicus suturalis Gyll.). The beetle is 2.5 - 3.5 mm long, dark brown, shiny, the depression on the slope is oval, has three teeth on each side, they are shifted into the cavity. The uterine passages are sinuous, sharply imprinted on the sapwood, three to seven passages depart from the breeding chamber, their length is up to 3 cm, width is 1.5 mm. Larval passages are frequent, long, winding. It settles on all conifers, prefers pine and cedar. Summer is in May, very extended. Young beetles hatch in. July and undergo additional feeding, being drilled into the wood. They hibernate under the bark, concentrating in 15 - 20 pieces. in the stellate passages of the near-bottom part of weakened trees (Zemkova, 1965). Generation is one-year. Actively affects the drying out of forest stands, traversed by fire. Dominates in poles, where it inhabits trees along their entire height.

Striped woodburner(Trypodendron lineatum Oliv.). Inhabits weakened pine trees, less often spruce and other conifers in the area of ​​thick bark simultaneously with the large pine beetle, but makes its paths in the wood. Generation is one-year, in the south (Crimea, Caucasus) is double, beetles hibernate in the litter. Shade-loving, hygrophilous species, goes to trapping trees. Causes great technical harm and spreads fungal disease - the blue of the wood.

A number of species of small bark beetles settle on the thin branches at the tops of the crowns of pines of different ages, which, with the apical type of tree dying off, can cause them significant harm. Among them, the Siberian engraver (Pityogenes irkutensis Egg.), The small steppe bark beetle (Carpohoborus minimus Fabr.), And others are very common.

On the spruce.Bark beetle (Ips typographus L.)(fig. 97). Beetle 3.5 - 5 mm long, dark brown, sloping depression on the elytral slope has four teeth on each side, located at an equal distance from each other; third tooth largest, thickened at apex. One to four uterine passages, 10 - 15 cm long, extend from the breeding chamber in the longitudinal direction. The larval passages are frequent, slightly sinuous, do not touch the sapwood (Fig. 98).

Fly in May - June. Beetles settle mainly in the lower and middle parts of the trunks on old and thick, less often young, spruces and trees of other conifers. Generation is one-year, in the south of the area - two generations per year. Additional food - in the places of development. Beetles overwinter in mine passages under bark or in forest litter. If the development of the second generation is delayed, the larvae and pupae overwinter in the passages and often die out during winter frosts. The species is light-loving, plastic.

The typographer is a dangerous pest of spruce, inhabits it in all cases of weakening, occurs in the mountains up to 1800 m above sea level, its mass reproduction has repeatedly been catastrophic.

Bark beetle double(IPS duplicatus Sahib.). Very similar to a typographer, but a little smaller... There are four teeth on each side of the wheelbarrow, but the two middle ones are close together and are on a common base. The strokes are slightly narrower and shorter than those of the typographer, sometimes slightly winding. The flight starts a few days later than the typographer's. Inhabits mainly younger and thinner trees, entering areas with thin bark. The species is photophilous, reproduces in sparse plantations, inhabits the remaining undergrowth in felling areas. It goes well for trapping trees.

Spruce engraver(Pityogenes chalcographus L.). The beetle is 2 - 2.9 mm long, dark brown, with a reddish-yellow narrow wheelbarrow, equipped with three teeth on each side. The moves are complex, star-shaped. Three to five uterine passages extend from the breeding chamber. Usually accompanies the two previous species, populating the tops and branches of trees of different sizes and ages. In the southern part of the range, spruce can give two generations per year. Additional food in the places of hatching of young beetles, where they winter. The species is light-loving, plastic, very widespread. In addition to spruce, it is often found on pine. It rarely populates weakened trees first.

Great spruce bark beetle-dendroctone(Dendroctonus micans Kug.). The beetle is 5.5 - 9 mm long, dark brown or black. The short uterine passage is enlarged from the side. The larvae gnaw a family passage in the form of a large cavity, filled with resin and clogged with sawdust. Beetles hatch in August. They hibernate and next year in spring the females gnaw out the uterine passages and lay 250 eggs each. The larvae hibernate. Generation is usually two years. Damages spruce and pine. In Georgia, it is a dangerous pest of eastern spruce, in the south of Western Siberia, of pine crops, in the European part of the USSR it forms clump foci in spruce and swampy pine forests. The biological cycle of dendroctone is characterized by a phase of an adult insect and larvae that is strongly extended in time, which can be found under the bark of trees at any time of the year (Kolomiets, Bogdanova, 1978).

Fluffy bastard(Polygraphus polygraphias L.). The beetle is 2.2 - 3 mm long, black-brown in color, covered with scales, which makes the elytra appear shiny gray from above. It flies in May - June, has one generation per year; prefers polewood and middle-aged spruce forests, inhabits trees with smooth bark, starting from 1 - 2 m in height. It is especially widespread in burnt-out areas and in foci of root sponge, in the taiga part of the forest zone it tends to be more sparse, and in the area of ​​broad-leaved forests to more dense plantations. It actively populates trees at the very initial weakening, it is not very willing to hunt trees.

Purple bark beetle(Hylurgops palliatus Gyll.). Equally often inhabits spruce and pine in the area of ​​thick and transitional bark; shade-loving and hygrophilous species; widespread in the forest zone, prefers windbreak and windfall; does not populate growing trees first.

In the taiga zone, a number of species of bark beetles are spread on spruce. Micrograph bark beetle (Pityophthorus micrographus L.) multiplies on thin branches in large numbers, in the middle part of the trunks there is a Chalceworm beetle (Xylechinus pilosus Ratz.), In the lower part there is an autograph bark beetle (Dryocoetes autographys Ratz.), Etc.

In Central Asia, a number of bark beetles live on the Tien Shan spruce, which are absent on other conifers. They do great harm and often contribute to the mass death of plantings. The most dangerous and widespread species is the mountain Kyrgyz bark beetle (Ips hauseri Reitt.). It flies in May, inhabits weakened old and middle-aged trees, windblows, southern edges along the slopes, undercutting in felling areas. This is a light and heat-loving species, in many ways reminiscent of a typographer and just as dangerous in mountain forests.

On a fir. Siberian fir is most often inhabited by bark beetles living on spruce. A typical pest of white-bark, whole-leaved and Sakhalin fir in the Far East and about. Sakhalin is the white-fir polygraph (Polygraphus proximus Blandf.). It actively colonizes fir in the foci of the Siberian silkworm, in places of talus, landslides, windbreaks and windblows, inhabits felled trees and piles of timber. Flight is very stretched and generations are confused; in Primorye, apparently, two, and in the Khabarovsk Territory and mountain forests - one. Supplementary food in the areas of hatching of beetles that hibernate.

Widespread on European, white and Caucasian fir hooktooth bark beetle(Pityokteines curvidens Germ.). It settles under the thick bark of weakened and felled trees, forms foci in places of erosion processes, in forests disturbed by felling and infected with fungal diseases. Summer is in May, generation is one-year, beetles hibernate in mine passages, in thick bark of growing trees. Causes significant harm in the Carpathians. The western kryphal (Cryphalus piceae Ratz.) Is also widespread, and in Primorye and on about. Sakhalin - Japanese kryphal (C. piceus Egg.). All kryphals are typical secondary pests and rarely colonize weakened trees first.

On larch(Siberian and Daurian). Throughout the range of larch is widespread oblong bark beetle(Ips subelongatus Motsch.). Beetle 5 - 6 mm long; the body is very elongated, a wheelbarrow with four teeth on each side. Typical inhabitant of larch forests. He makes long passages, reminiscent of those of the six-toothed bark beetle, in the lower and middle parts of the trunk, occasionally under the thin bark. Flight of beetles in May - June, generation is one-year, additional feeding in places of development, beetles overwinter in mine passages and in the upper layer of soil under moss. The species is plastic, however, it gravitates more towards illuminated, well-warmed places, where it attacks weakened, but still viable trees and unrooted timber of winter harvesting. Especially great harm is done in the foci of the Siberian silkworm. It can settle on Siberian cedar and occasionally on spruce.

Found on larch sapwood Moravitz(Scolytus morawitzi Sem.) Is the only sapwood living on conifers, but HeimeeT is massively distributed. The Baikal woodland (Dryocpetes baicalicus Reit.) Is much more common, but it also does not matter much. Bark beetles from pine and spruce settle on larch: a six-toothed engraver, a typographer, etc.

On hardwoods. There are many species of bark beetles. However, not all species are of great economic importance. Only the most common and harmful species will be considered here.

Birch sapwood(Scolytus raizeburgi Jans.). Distributed throughout the range of birch to the Far East. Inhabits the lower and middle parts of the trunks, making simple longitudinal passages under the bark with many round holes along the uterine passages, along which it is good to distinguish the trees inhabited by it. Flight of beetles in May, additional feeding in bark near buds, laying of eggs in June, larva overwinters in passages, generation is one-year.

The species is plastic, but prefers to settle on trees growing singly or in groups at forest edges, near roads, in sparse plantations and parks. Inhabits heavily weakened and dying trees.

In Primorye, very similar to birch is widespread Amur sapwood(S. amurensis Egg.). Most often, it is found in ash-tree swampy forests with an admixture of Manchurian birch, where it inhabits birch windblown trees, and sometimes causes their summit withering away, damaging the top and thick branches.

Oak sapwood(S. intricatus Ratz.) Fig. 99). It is found throughout the oak range in the European part of the USSR and in the Caucasus, where it inhabits local oak species (Armenian, etc.). Occasionally settles on hornbeam, chestnut, birch, maple and other species, but is not considered a pest. Inhabits mainly dying young oaks along the entire trunk, and on older trees avoids thick bark and inhabits their middle part, tops and branches. The uterine passages are transverse, simple, short.

The beetles fly in June, after which they feed additionally in the crowns of perfectly healthy oak trees for 10 - 12 days. To do this, beetles are introduced into thin terminal branches at their joints. Initially, they make superficial gnaws and only after a few days they completely go deep into the branch, making a stroke about 0.5 cm long on it. Oviposition in the second half of June - July. The larvae overwinter, they pupate next spring in late April - early May. Generation is one-year.

During additional feeding, beetles very often spread the infection. vascular disease oak (Ceratocystis), infecting more and more trees with it as it spreads (Edelman and Malysheva, 1959). Outside the foci of the disease, it is a rather passive pest.

Ilm breeds. Many species of sapwood and bark beetles are found on the elm. Mass reproduction is periodically observed in the steppe and forest-steppe zones Oh. Sapwoods carry Dutch disease (Graphium ulmi) infection with supplementation. Additional feeding of beetles takes place in the joints of thin twigs in the same way as in oak sapwood. Trees infected with Dutch disease lose their stability and are colonized by sapwoods, although outwardly they still look completely healthy. At the same time, the curtain drying of elm occurs, due to the small radius of spread of sapwoods, usually equal to 70 - 130 m.

The most common types of sapwood that carry Dutch disease are: sapwood destroyer(Scolytus scolytus F.), streamy sapwood(S. multistriatus March.) (Fig. 100), Both sapwood populate birch bark, elm and elm of different ages, mostly older than 8-10 years.

The destroyer sapwood gravitates to the lower part of the trunks, and the streaky one - to the middle and upper parts, also inhabiting the branches.

The destroyer sapwood in the steppe part prefers birch bark, on which two full and partial third generations develop. On an elm tree, the flight of young destroyer beetles is delayed by two to three weeks. The streaky sapwood on birch bark develops in a similar way, and on the more preferred species - elm - there are only two generations. The flight of beetles, their colonization of trees and the development of the young generation are very extended in both species. In the period from May to September, larvae, pupae, young beetles and the beginning of new settlements can be simultaneously found. To the north, the number of generations per year is reduced to one, and in the Caucasus and Central Asia it is increased to four. In a number of areas (southeast of the European part of the USSR), the sapwood-destroyer on the elm is replaced by a closely related sapwood wrinkled(Scolytus sulcifrons Rey.).

In the upper part of the trunks and on the branches of the elm they settle sapwood pygmy(S. pygmaeus F.) and sapwood kirsha(S. Kirschi Seal.). They often inhabit elm trees in ravine forests, along gullies, in floodplain forests and shelter belts and are also carriers of the Dutch disease. The pygmy sapwood develops similarly to the striate, and the Kirsch sapwood has only one generation per year, the flight of beetles in June - July. In the North Caucasus, in the Crimea and some other regions, it is distributed sapwood Zaitsev(S. Zaitzevi But.), Whose biology is similar to Kirsch's sapwood.

Along with sapwoods, trees inhabit elm bark beetle(Pteleobius vittatus Fabr.) And bast beetle Kraatza(P. Kraatzi Eichh.). They appear in April - May, the emergence of young beetles in August. Beetles hibernate in the bark of the butt of the trunks of growing trees.

Ash. Ash beetles do great harm to ash. Of these, the most common and dangerous small (variegated) ash bark beetle(Hylesinus fraxini Panz.). It inhabits ash trees of various ages, mainly young and middle-aged, within the European part of the USSR. During mass reproduction, beetles inhabit apparently perfectly healthy trees, often causing the forest stand to dry out. Flying in May (in the south from mid-April), the passages under the thin and middle bark are transverse in the form of curly braces. Generation is one-year. Additional food in mine passages on thin parts of the trunk, and wintering in the same passages in the thick bark, in the same places from year to year. As a result, there are painful growths in the form of rosettes.

In the forest-steppe and steppe zones, the large ash beetle (Hylesinus crenatus Fabr.) Is also often found, in the same place and in the Caucasus - the oil beetle (N. oleiperda F.), and in the forests of the Far East - the motley Ussuri bast beetle (H. eos Spess. ) and black bark beetle (N. laticollis Blandf.).

On fruit trees, ubiquitous wrinkled sapwood(Scolytus rugulosus Ratz.). It also damages bird cherry, hawthorn, mountain ash, dogwood; has a number of subspecies common in the Caucasus and Central Asia. It attacks weakened trees, inhabits trunks with thick bark, and on old trees it occupies their middle and upper parts and branches. Generation is one-year, in the south - double, additional nutrition in the cortex at the base of the kidneys.

Woody bark beetles cause great harm to deciduous species. The most common of them ladder deciduous woodcutter(Trypodendron signatum 01.), outwardly differs little from the coniferous wood-grower, leads the same way of life, but always inhabits only deciduous species, especially oak, birch and alder. Unpaired woody species are also widespread, which got their name due to the difference between males and females. Females lay eggs in a heap; the larvae gnaw a joint family passage or creep along the uterine passages. The most simple moves are arranged in the polyphagous woody grower (Xyleborus saxeseni Ratz.), Which attacks many deciduous species (oak, beech, alder, hornbeam, hazel, etc.), and in the Far East and conifers. Flying at the end of May - June. Generation is one-year. Inhabits weakened trees (Fig. 101).

Have western unpaired woodcutter(Xyleborus dispar Fabr.) The course is constructed differently from that of other unpaired woodcutters. The female first sharpens the canal perpendicular to the surface of the trunk by 3 - 6 cm, where the stroke turns along the annual ring in one direction or the other, ringing the trunk. From this initial move, the female lays eggs in heaps. Flight of beetles in June; young beetles overwinter in passages. Generation is one-year. The species is polyphagous, especially damaging to oak, beech, maple, birch and fruit trees. In the conditions of the steppe zone, it is considered a very harmful species; it is also found in Siberia and the Caucasus.

All wood-growers are at the same time technical pests, the fight against them is obligatory (Chapter X).

Longhorns (Cerambycidae)

The family of longhorn beetles unites about 17 thousand species of beetles on the globe, of which only 1,500 species live in the USSR. Longhorns feed on plants, and most of the barbel live off trees and shrubs and are called lumberjacks.

The sizes of barbel beetles range from 3 to 60 mm. The body is elongated, most often covered with hairs. Legs long, tibiae with spines, tarsus 4-segmented. The head is free. Antennae longer than half of the body and often 1.5 - 2 times larger than it. All woodcutters have an inherent ability to "throw antennae over their backs", that is, bend them back, which other beetles cannot do. The elytra cover the entire abdomen; occasionally, the elytra are greatly shortened and the abdomen remains partially uncovered (short-winged barbel p. Molorchus, etc.). Most longhorn beetles are capable of making a squeaky sound when rubbing the mesothorax against the prothorax. Barbel larvae are equipped with small, but well adapted jaws for gnawing wood. With their help, they gnaw through long and wide passages in wood. Adult larvae are cylindrical or slightly flattened, white. The head and jaws are firm and brown in color. The front end of the body is wider due to the expanded front chest. On the segments there are special platforms - "calluses", resting on which the larvae move in their passages.

Barbel larvae vary greatly in body structure, head size, absence or presence of legs, but at first glance they are all similar to each other, have similarities in basic structural features and are easily distinguishable from larvae of other stem pests.

The flight of woodcutters takes place at different times and is very extended, since the conditions for their development in a tree are very changeable and depend on its condition, age, habitat and the variability of individual tissues that the larvae feed on. A number of species fly in early spring, simultaneously with pine beetles, most in June - July, in some longhorn beetles the flight is delayed until the end of August.

The calendar terms of flight of certain species are determined by the weather conditions of the year and the geographical area.

Females lay white oblong-oval eggs in cracks and crevices in the bark and wood, or in depressions gnawed in the bark (notches). Egg development lasts 10 to 20 days. The larvae emerging from the eggs begin to gnaw the passages in the bast.

According to the way of life, the larvae can be divided into several groups:

the larvae spend their whole life under the bark, where they gnaw passages and pupate;

the larvae spend most of their life under the bark, gnaw out long passages, and before pupation they go into the wood and make a small hook-shaped move;

the larvae do not live under the bark for long, gnaw out a small area in the bast and then make long passages in the wood, bringing them to the surface of the wood before pupating; such a course after the beetle emerges has a staple shape (Fig. 103).

The larvae spend their entire life in wood. Most lumberjack larvae have round-oval passages. The larvae usually hibernate once or twice and pupate in the spring. The duration of development of larvae can vary depending on the state of the wood and feeding conditions.

Before pupation, the larva almost always arranges a special cradle, that is, expands the end of the stroke. In the cradle, the larva pupates. If the larva makes a hook-shaped course, then it turns over before pupating with its head towards the exit. In the event that the larva gnaws through the staple passage, it does not turn over, and the young beetle gnaws the remaining space. Before pupation, the larva usually separates the cradle from the rest of the stroke with a sawdust plug. Pupal development lasts 10-12 days.

Barbel generation is different. In many species it is one-year, in others it lasts two to three years. The duration of generation is influenced by the feeding conditions of the larvae. Under unfavorable conditions, generation is delayed for several years.

After emergence, young beetles in many species undergo additional feeding on the juicy bast of young shoots in the crowns (black barbel beetles), gnaw out leaf tissue (aspen squeaks), or feed on pollen from flowers (more species).

Among the barbel, oligophages predominate, feeding on a number of tree species close in origin. All longhorn beetles are divided into pests of coniferous and deciduous trees. From conifers to deciduous longhorns are very rare, although such cases are known. Thus, the large black coniferous barbel in Eastern Siberia develops on fir, spruce and birch. Among the longhorn beetles of the same genus, very often some species are associated with conifers, and others with deciduous species.

Within conifers and deciduous species, longhorn beetles also have a preference for well-known tree species. So, the gray long-wattled barbel and the barbel of pine tops very rarely develop on spruce, and the shiny-chested barbel - on the pine. The same picture is observed when feeding on deciduous trees. The transition from one breed to another often leads to a delay in development, the timing of emergence, fertility, and changes the size of the body. The preference for a particular tree species depends on different geographic areas.

Each species of barbel occupies a certain area of ​​the settlement on a tree (roots, thin branches, part of the trunk with coarse or thin bark) and rarely changes its habits.

Some longhorns are very active and inhabit apparently perfectly healthy trees (large and small aspen barbel, etc.). Most attack weakened trees. Among the longhorn beetles, there are light- and heat-loving forms and shade lovers, most of the species have great biological plasticity.

The change in the number of barbel depends on the complex of factors discussed above for the entire group of stem pests.

The abundance of species of longhorn beetles does not allow in a short course to give them any satisfactory overview. Therefore, the following is a description of only the most common and harmful species.

Black coniferous barbel (p. Monochamus). Large insects, their body is more or less elongated. It is usually shiny, black, or pitch black. The elytra are long, in most cases, strongly elongated, slightly narrowed towards the end, usually rounded, with a coarse sculpture and thick lighter hairs. Antennae more or less slender, 1.5 times as long as body, with one segment strongly thickened.

The larvae are white, legless, the head is black, the body is somewhat narrowed towards the end. The size of the larvae depends on the species and reaches 4 - 6 cm in the fir barbel. They first gnaw out large, irregularly shaped areas under the bark, and then go deeper into the wood, where they make very large, staple-shaped passages. So, in a fir barbel, the length of the vertical part of the stroke is 15 cm, the total stroke length is 30 - 40 cm, and the width is 1 - 2 cm. The aperture 1 is 1.2 cm.

All black longhorns undergo additional feeding in tree crowns, damaging shoots and branches.

The following types of black barbel are widespread in the forests of the USSR: black large coniferous barbel (M. urussovi Fich.), Black pine barbel (M. galloprovincialis Gelb.), Black small coniferous barbel (M. sutor L.), velvet-spotted black coniferous barbel (M. saltuarius Gelb.) And black coniferous speckled barbel (M. impluviatus Motsch). The last two species are found only in the forest zone of the Asian part of the USSR, the rest are ubiquitous.

Black coniferous barbel(Monochamus urussovi Fisch.). The greatest harm is caused in the forests of Siberia and the Far East, multiplying in huge quantities in the foci of the Siberian silkworm and fir moth, in burnt-out areas, as well as in forest yards and in places of large logging. In the European part of the USSR, this species is widespread in the northern part of the forest zone and relatively few in its southern part (Fig. 102).

Mass flight of beetles in the forests of Siberia begins at an average daily temperature above 13 ° С, at temperatures above 20 ° С the flight intensity increases, and when it falls below 10 ° С, it decreases. Usually flight begins in the third decade of June, is massive in the first two decades of July, and ends in mid-September. On about. On Sakhalin, flight begins almost a month later (Krivolutskaya, 1961), and in the southern part of the forest zone - 1 - 1.5 weeks earlier.

Beetles live for about two months (according to Prozorov, on average 51 - 52 days) and during this time they undergo additional feeding in the crowns of trees of different ages (starting from 10 - 12 years). Usually, the beetle selects a thin branch, places it along it, bites the existing needles and then begins to scrape off the bark, exposing the wood in a strip along the length of the branch by 1-10 cm.

Oviposition begins 12 to 20 days after the first beetles appear, and in another 10 to 12 days it reaches its maximum. In the southern part of the forest zone of the European part of the USSR, oviposition begins 8 to 12 days after the appearance of the first beetles. To lay eggs, the female gnaws a narrow slit in the bark - a notch into which, with the help of the ovipositor, inserts one, rarely two eggs to a depth of 2 - 3 mm. The average fertility of one female is 14 eggs, the maximum is 33. The egg phase lasts 13 - 29 days; for its development, a sum of temperatures of about 250 ° C is needed.

The larva that emerged from the egg has a body length of about 3 - 5 mm and gnaws a passage in the thickness of the bark, and then in the sapwood and hibernates in the first or second instar. In the second instar, it widens its passage under the bark and deepens into the wood up to 5 cm. The second molt occurs in June of the following year. At this time, the larva penetrates even further into the depths of the trunk, cleans the passages all the time and periodically returns to feed under the bark. At the fourth instar, the larvae rarely visit the subcrustal space. At the last - fifth instar, which occurs after the fourth molt in the fall of the second year or in the spring of the third year after the egg phase, the larva no longer returns under the bark, but ends its course at a distance of 1.5 - 2 cm from the surface of the trunk and at the end it suits a pupal cradle, in which in the third year it turns into a pupa (Fig. 103). The pupal phase lasts 25 to 26 days. The generation is two-year, but under favorable conditions of development, part of the population can complete the life cycle in one year.

The large black coniferous barbel can inhabit all conifers of the taiga, but prefers fir, and in the forest zone of the European part of the USSR - spruce. In addition, in the conditions of Transbaikalia and Mongolia, it settles on a birch, where it successfully completes its feeding, including additional feeding (Tal'man, 1940; Grechkin, 1960).

Longhorn beetles are photophilous and primarily settle in windows, along forest edges and in sparse plantations, however, during mass reproduction, these features are erased and the beetles spread regardless of lighting. They inhabit fallen and standing trees, but the first ones are denser.

In the foci of the Siberian silkworm, first of all, fir is inhabited, then spruce and Siberian cedar. The barbel is less common on larch and plays a secondary role. He prefers trees with a diameter thicker than 24 cm, and avoids thin trees (8 - 12 cm) (Kataev, 1959). It populates mainly the lower and middle parts of the tree trunk, where development proceeds somewhat faster, and the mortality of larvae is less. On the whole, the barbel has a very high embryonic mortality and the death of up to 50% of the larvae (Lonshchakov, Maslov, Michel, 1958), although the activity of entomophages is comparatively inactive. Many larvae are exterminated by woodpeckers, especially woodpeckers (Prozorov, 1958).

Black pine barbel(Monochamus galloprovincialis Germ.) (Fig. 104). A dangerous pest of pine forests in the southern part of the forest zone, forest-steppe and steppe zones of the European part of the USSR, belt pine forests in Western Siberia and Kazakhstan. It reproduces in the foci of the root sponge, on burned-out areas, in the foci of needle-gnawing insects, in pine forests heavily weakened by drought, in pine bedbugs, in logging sites and in timber warehouses.

The flight of beetles begins in the first ten days of June; at the beginning of July, 90% of them leave the wood (Kuznetsova, 1956). The beetles hatch immature and undergo additional feeding on pine branches, gnawing at the fresh thin bark. Beetles live up to 70 days, but after 5 - 7 days, females begin to lay eggs in the notches. The larvae appear in mid-July. They feed on bark, bast, sapwood and upper layers of wood. In early August, the larvae go deep into the wood. As in the fir barbel, the larvae periodically crawl out of the passages into the subcrustal space throughout their development to feed on bast and sapwood. In this regard, they clean and widen their passages, sometimes make additional holes to eject "sawdust". The end of the stroke in the wood does not bring the larva 1-1.5 cm to the surface, and at the end of it it arranges a doll's cradle, where it hibernates. Pupation occurs in May. Generation is one-year, but some of the larvae develop in a two-year cycle.

Longhorn beetles are photophilous and prefer sparse, well-warmed plantings. In mixed plantations, the number of barbel drops sharply. It settles along the entire trunk, while in the butt part there are more females, and in the upper part, males.

The biology of the rest of the blacks coniferous barbel very similar to the above two leading species. They also fly from late June to August and develop in a single-year cycle, populating various conifers.

Longhorn Tetropiums (p. Tetropium). They are distinguished by their smaller size and flattened body of beetles. Antennae reaches half of body, pronotum is almost as long as wide, elytra slightly convex, moderately long, parallel, usually much wider than pronotum, rounded at apex, black or chestnut; the body is black.

The larvae are characterized by the presence of short legs; they are yellowish-white with darker pronotum and head, jaws black, head almost cordate, dorsally with longitudinal groove in the middle. The size of the larvae depends on the species and reaches 20 mm. They gnaw out areas under the bark, and then make a hook-shaped course in the wood, where they pupate.

The following species are widespread in the forests of the USSR: brilliant-breasted (T. casianeum L.) and dull-breasted (T. fuscum F.) spruce barbel, Gabriel's larch woodcutter (T. gabrieli Weise.), Thin-wooded spruce barbel (T. gracilicorne Reitt.) and the Semirechensky spruce barbel (T. staudingeri Pic). The lifestyle of all these species has a lot in common. All of them damage conifers and are active pests, attacking the first on weakened trees in the centers of pine-gnawing insects, honey fungus and root sponges, inhabiting weakened trees along the edges, windfall and windbreak, wood in logging sites.

Gleaming spruce barbel(Tetropium castaneum L., p. 105). Distributed throughout the USSR. Flight in May - June; the female lays eggs in the cracks of the bark of the trees, the larva gnaws wide irregular passages under the bark, deeply touching the sapwood, and after 20 - 25 days leaves, makes a hooked move into the wood to a depth of 2 - 4 cm.In this move, she hibernates, and turns in spring to the exit and pupate. Generation is one-year.

The barbel settles on spruce trees of different diameters, in various environmental conditions, mainly in shaded places, inhabits the butt part of the trunks, and in Siberia, in the foci of the Siberian silkworm, it settles before the fir barbel and occupies the entire trunk, damaging, in addition to spruce, Siberian cedar. It is rare on other conifers.

Altai larch barbel(Xylotrechus altaicus Gelb.). The beetle is 11 - 23 mm long. Females are larger than males. The body is elongated, narrow, brown in color, the legs are long, the pronotum is massive, almost spherical. Elytra grayish brown. Distributed from the Urals to the Pacific Ocean.

Mass flight in July. Beetles don't eat. Females lay eggs intensively in the first five to six days, and after two weeks they stop laying completely. They place their eggs in the crevices of the bark one by one, mainly on the southern side of the trees, placing them along the entire height of the trunk. Fertility of one female is 50 - 102 eggs (Rozhkov, 1981). Egg phase 13 - 16 days. The hatched larva is legless, white, with a reddish tinge. The length of an adult larva is about 32 mm. The larva goes through five instars. After the release of their eggs, the larva bites into the bark, destroys the bast, hibernates in the bark. In the spring, under the bark, it makes a course along the circumference of the trunk. and in July - August it goes deep into the wood, where it hibernates again. After the second wintering, the larva approaches the periphery of the trunk, arranges a pupal cradle and pupates. Pupal phase 16 - 20 days, generation 2 years.

The holes laid by the larvae in the outer layers of the sapwood are very characteristic. They have transverse directions and do not intersect even with a very dense arrangement, they are clogged with sawdust throughout. Damaged trees are very characteristic and can be recognized by the moves described above (Fig. 106).

The species is light and thermophilic. The outbreaks arise primarily in old, sparse plantings damaged by fire or pine-gnawing pests. It is a physiologically active species. It populates trees with a slight decrease in their resistance. Reaching a high number in breeding centers, it also settles on healthy trees. A characteristic feature of the barbel is the formation of new foci due to migration. According to A.S. Rozhkov (1981), the larch barbel is of great economic importance. It is the most dangerous pest of larch. It does not harm other tree species - strict monophage.

Gray long-wattled barbel (Acanthoclnus aedilis L.). Body flat, light brown, gray underwings with dark bands. Length 13 -20 mm. Antennae 1.5-3 times as long as body. The most common inhabitant of pine forests. It is ubiquitous in large numbers, but, as a rule, it attacks only dying and fallen trees, stumps, windfall, windbreak. It does not harm the wood, since the larva gnaws wide irregular passages only in the bark and bast. The larva is legless, white, 30 - 34 mm long.

The flight of the barbel begins very early, usually at the end of April - May, it is very stretched, and the beetles can be found until August. Development proceeds rapidly, and in autumn, young beetles are found in oval cradles under the bark. At a later hatching of the larvae, they hibernate, and young beetles appear only in spring. Generation is one-year.

With a large number of barbel larvae, they eat away the entire subcrustal space, clogging it with compressed brown sawdust, and thereby prevent the settlement of other stem pests, especially bark beetles.

In the forests of Siberia and the Far East, conifers and other representatives of p. Acanthoclnus: Siberian long-wattled barbel (A. carlnulatus Gelb.) And Lesser gray long-wattled barbel (A. griseus F.).

Ragium ribbed (Rhagium inquisitor L.) accompanies the gray long-wattled barbel, has the same development cycle. Its larvae with a bright orange-brown head, live and pupate under the bark of dead coniferous trees. This species is very widespread, but does no harm. Other species of this genus (Rh. Mordax Dg. Rh. Sycophanta Schr.) Develop from deciduous trees and are also practically harmless.

In the butt of coniferous trees and fresh stumps, three species of widespread barbel live: the brown barbel (Criocephalus rusticus L.), the black ribbed barbel (Asemum striatum L.) and the short-toed barbel (Spondylis buprestoides L.). Only the first of them does noticeable harm. The other two are rather beneficial, accelerating the destruction of stumps and the biological cycle in ecosystems dominated by double (mainly pine) species. In the literature, however, there are a number of indications of harm caused by the larvae of these longhorn beetles in dry pine forests.

Brown butt(or rustic) barbel(Criocephalus rusticus L.) causes technical harm, and also participates in the complex of the spring phenological grouping of stem pests inhabiting weakened various factors(fires, root sponge, etc.) trees. It is a large reddish-brown beetle, 10 - 27 mm long, short antennae. Beetles are nocturnal, willingly fly into the light into houses. Summer is in June - July. Females lay eggs in stumps, roots and the lower part of dying pine trees, less often in other conifers.

The larva is yellowish-white with black-brown jaws, up to 33 mm long. She first lives under the bark in the area of ​​thick roots or the root part of the trunk, then goes into the wood and makes longitudinal passages, clogging them with brownish flour. At the last instar, the larva arranges a cradle for pupation and gnaws out the outlet to the lateral surface, clogging it with coarse drilling flour. The pupal phase lasts three to four weeks. The hatching beetles do not need additional nutrition and immediately start mating. Generation lasts one to three years, depending on the substrate. Prefers pine. It is often found in the wood of cold buildings, unbarked logs, telegraph poles.

Hardwoods damage many barbel species. The main ones are listed below.

Large oak barbel(Cerambyx cerdo L.) damaged oak forests in Ukraine (west of the Dnieper) and especially in Crimea, Georgia and Krasnodar Territory. A very beautiful large beetle up to 6 5 mm long (Fig. 107. Now it has become a rare species and needs protection.

The flight of beetles is from mid-May to August. The female lays eggs one at a time in the cracks in the bark, up to 100 eggs in total. The egg phase lasts 10 to 15 days. The larva gnaws the passage under the bark for the first year, after wintering it goes deep into the wood, where it makes an irregular channel up to 3 cm wide, hibernates again and pupates at the end of the passage in the third year. A beetle hatches from the pupa in July - August, but leaves the tree only in spring and additionally feeds on oak sap. Generation is three-year.

The species is light-loving, settles on the southern edges, in sparse, mostly old stands of coppice origin, where it inhabits, first of all, the thickest, well-lit, outwardly quite viable oaks.

In the Caucasus, along with oak, similar to bliss is common large fruit barbel(Cerambyx dux Fald.), Damaging oak, beech and fruit species, and in oak forests of the forest-steppe - small oak barbel(C. scopolli Fussl.). In addition to oak, it damages beech, hornbeam, ash, maple, elm and fruit trees, but usually does not form foci and is of little economic importance.

Variegated oak barbel (Plagionotus arcuatus L., P. detritus L.). They are very widespread within the boundaries of the oak range in the European part of the USSR and in the Caucasus. From a distance, they resemble wasps a little in coloring. The body is black with arcuate yellow stripes in one species (P. arcutus L.) and wide yellow constrictions in another (P. detritus L.). Mass flight in June, oviposition in bark cracks along the entire trunk, larvae gnaw long longitudinal passages, expanding as they grow and deeply touching sapwood. On standing oak trees, they are directed upward, and on lying trees and logs, they have an indefinite direction. In 30 - 40 days after emerging from the eggs, the larvae gnaw through oval holes and go into the wood to a depth of 2-4 cm, then abruptly, almost at a right angle, bend down and gnaw a course along the wood fibers up to 3 - 5 cm long. larvae overwinter, plugging the horizontal part of the passage with a cork made of wood stubs, and in the spring they expand the passage, turn over with their heads towards the exit and pupate. The pupal phase lasts about 20 days. Young beetles widen the entrance holes. Generation is one-year. These species contribute to the death of often still viable trees and cause great technical damage, rendering oak wood unusable. Plastic species are found in a wide variety of conditions.

Yellow-spotted barbel (Mesosa myops Dalm.) distributed everywhere, including the Far East. It damages most hardwoods, especially oak. Flight from June to late August; the larva makes long passages under the bark, where it pupates, beetles hibernate, additional food on the bark of trunks and branches, generation is one-year. A very plastic species, found in a wide variety of environmental conditions.

On the weakened and felled oak trees, a whole series of longhorn beetles settle, the larvae of which gnaw through rather deep passages in the wood. These barbel beetles open the gates of fungal infection and greatly reduce the technical qualities of the wood. The main species are: Kehler's red-winged barbel (Purpuricenus kaehleri ​​L.), red oak woodcutter (Phyrrhidium sanguineum L.), antelope barbel (Xylotrechus antilope Schonh.). They fly from late May to July. The larvae hibernate in wood. Generation is one-year. Beetles inhabit trees of different diameters, however, they prefer oak trees of medium thickness, young, middle-aged.

Great Aspen Barbel(Saperda carcharias L.). This species is widespread in the European part of the USSR and Siberia (Fig. 108).

The beetle is 21 - 28 mm long. Light brown or gray due to the hairs that cover it. In males, the elytra taper posteriorly; in females, they are almost parallel. The last segments of the antennae are covered with black rings. Fly from late June to September (peak in July). Beetles undergo additional feeding, gnawing round holes in aspen and poplar leaves, and transverse slit-like bark gnaws on shoots, thin trunks and branches. After mating, the females make notches in the butt of the growing trees and lay one egg at a time. Fertility of one female is 50 - 60 eggs.

The larva first gnaws a cavity in the sapwood of an irregular shape and then deepens into the wood, where it gnaws a long (up to 1.5 m) vertical passage, in which it hibernates again, and in the spring of the third year makes a lateral flight and pupates at the upper end of the vertical passage on a previously prepared stopper made of fibrous shavings. The young beetle, having destroyed the cork, makes its way into the side passage and gnaws a round flight hole through which it comes out. Generation is most often two-year, but it can take up to three to four years.

In areas north of Moscow, eggs most often winter, occasionally the larvae of the first instar (Pavlinov, 1965), in more southern places the larva has time to gnaw through a passage in the form of a cavity under the bark. The direction, configuration and size of these moves depend on the age of the tree. The most sinuous and large cavities are found on young trees. In this case, the larva often gnaws several holes in the bark, from which it throws out sawdust. Later, the larvae on all trees begin to bite into the sapwood. In this case, the direction of the moves can be different. Most often, the larvae bite in a tangential direction, gradually rising upward. However, when laying eggs directly at the root collar, the passages first go down. In the future, the larva rises up and begins to gnaw a typical core course. By this time, the lower part of the passage is usually densely clogged with sawdust. The length of the vertical stroke is different. On average, it is 30 - 40 cm. On old trees, the length of the passages can reach 1 - 1.5 m.

The adult larva reaches a length of 42 mm (at the first instar about 6 mm). She is whitish-yellow, legless, with sparse hairs.

Before pupation, the larva gnaws a lateral passage to the surface of the trunk approximately in the center of the vertical passage. Pupation occurs on a dense sawdust plug at the top of the stroke. The pupal phase is about 15 days. The hatched beetle gnaws a round hole, which quickly overgrows. Generation in the northern part of the range is three- and four-year (Pavlinov, 1965). For the southern part of the range, along with a four-year one (Petrova, 1956), a two-year one is indicated (Grechkin, 1960).

With a high density of colonization of trees, the barbel causes their gradual drying out. At the same time, it also causes technical harm, since wood eaten away by larvae completely loses its technical properties. In addition, redness is intensively spreading on the branches from the larval passages and beetle incisions.

Lesser Aspen Barbel(Saperda populnea L.). Causes great harm to young aspens and poplars. Fly in May - June. Generation is two-year. The damaged branches and trunks, inside which the larva develops, are clearly visible by the galls formed in the places of oviposition and penetration of the larvae into the shoot (Fig. 109).

Gray aspen barbel(Xylotrechus rusticus L.). It is the most widespread and numerous inhabitant of deciduous forests. Flight of beetles is prolonged, begins in May and lasts until mid-August with a peak in June. Females lay eggs in crevices and cracks in the bark of standing, weakened and felled trees, as well as various timber.

The larva first gnaws at the passage under the bark, deeply touching the sapwood. The course is winding, sometimes with extensions and spurs, all clogged with drill meal. In the outer layers of wood, it usually goes more or less parallel to the surface of the wood, then deepens obliquely, in thin trees it often reaches the opposite side. On thicker trunks, the passages are bent and directed towards the surface of the wood. At the end of development, the larva comes close to the surface of the wood and pupates there. Generation is two-year, and cannot be completed in one year.

Marble patterned barbel(Saperda scalaris L.). The beetle is greenish in color with black spots on the elytra, forming a marble pattern. The length of the beetle is 12 - 20 mm. Inhabits birch, aspen, alder and other deciduous species. The female lays eggs in depressions, which she gnaws in cracks in the bark. Fertility is 10 - 30 eggs (Trofimov, 1980). The larva sharpens a winding path under the bark, then goes deep into the wood, where it makes a hooked short stroke. The generation is one-year, but a number of authors indicate a two-year one (Trofimov, 1980).

Urban, or Uzbek, barbel(Aeolesthes sarta Sols.). It is widespread in Central Asia, where it causes great harm to many tree species, especially poplars, sycamore trees, white acacia, walnuts, etc. growing in urban conditions. elytra (Fig. 110). The flight of beetles is from late April to mid-June. Females lay one by one - three eggs in cracks and depressions in the bark of tree trunks of all ages, more often old ones. Only one female lays up to 270 eggs. The hatched larvae bite under the bark, first feed on the bast, then make winding passages that strongly touch the sapwood, and pass into irregular oval cavities, sharply cutting into the bast and cork of the bark. In autumn, the larvae go deep into the wood and hibernate there, and the next year they continue to move. First, it is laid down, then it bends sharply in a hook-like manner and goes up, parallel to the surface of the trunk. Young beetles appear at the end of summer and hibernate in passages. Generation is two-year.

The urban barbel attacks seemingly healthy, still quite viable trees and gradually leads them to death. It is found in valleys and mountain forests up to an altitude of 1800 m above sea level.

Goldfish (Buprestidae)

The family of golden beetles unites beetles of various sizes (from 3 to 80 mm), the overwhelming majority of which live in tropical countries. In the USSR, the goldfish fauna is especially diverse in the Caucasus and Central Asia. In the European part of the USSR, only about 180 species are found. They are mainly associated with trees and shrubs. Many species are dangerous pests of tree species, especially in the steppe zone, where they are one of the main stem pests.

The beetles have a flat, elongated body narrowed towards the end, metallic-shiny, with brightly colored hard elytra. The head is small, the legs are short, the tarsi are five-segmented, the antennae are 11-segmented, serrate. The shape of the body and well-developed hind wings facilitate fast and long-distance flights of golden beetles and their distribution over the territory.

Goldfish beetles are exceptionally light and thermophilic. They fly, mate and lay eggs only in bright sunlight, gravitate towards well-lit and warm habitats.

Females lay their eggs in cracks and crevices in the bark or on its smooth surface with an illuminated, usually southern part of tree trunks. Sometimes they fill the clutches of eggs on tree trunks with a liquid secreted by special glands. The liquid instantly freezes, and numerous white caps are formed on the tree trunks, under which there are eggs (green narrow-bodied goldfish and a number of other species of p. Agrilus). A small group of species of goldfish lays eggs on leaves, which are then mined by larvae (p. Trachys). Finally, there are goldfish, the females of which lay their eggs in the ground near the roots of trees. The hatched larvae find the nearest root and begin to feed on it, gnawing long winding passages towards the surface (goldfish p. Capnodis).

The larvae of the goldfish are highly elongated, uncolored, yellowish-white, legless, blind, with a characteristically widened and flattened upper and lower prothoracic segment, bearing one or two anteriorly converging grooves from above. The head is small, dark, retracted into the prothorax. The larvae of goldfish are dry to the touch and can tolerate high temperatures under the bark of a tree (up to 48 ° C), reconciling with the great dryness of the substrate and air, which contributes to their survival in the interspecific struggle against larvae of other stem pests.

According to their lifestyle, the larvae of the goldfish are divided into several groups. Some of them all develop under the bark, feeding on bast and sapwood, others finish their development in wood, and still others feed on wood almost all the time.

Under the bark, the larvae gnaw flat, with sharp edges, winding, gradually widening passages, densely clogged with sandy wavy drill meal. Sometimes the course intersects several times and forms at the end a characteristic tangle (green narrow-bodied goldfish). Most often, the passages have a transverse direction and first pass through the bark and bast without touching the sapwood. On conifers, this allows goldsmiths to be the first to populate trees, since their passages almost do not violate the system of resinovers (blue pine goldfish). In wood, the passages are short in the form of a hook (for example, in p. Chrysobothris). Only a few species of goldsmiths, making long passages in old stumps, posts and logs (p. Buprestis), bring technical harm to wood. A number of species live in the roots of trees growing in the desert (dzhuzgan, comb, saxaul, etc.), exhausting them in all directions.

The larvae usually hibernate once or twice and pupate in pupal cradles in spring. Young beetles emerge from pupae in two to three weeks. They gnaw through the flight hole, which has the shape of a more or less elongated, sometimes very narrow ellipse. One side, corresponding to the back of the beetle, is flatter, the other, corresponding to its abdominal surface, is more convex.

After emergence, young beetles in many species undergo additional feeding on flowers and leaves. Generation in goldsmiths is most often one- and two-year.

Pests of deciduous species predominate among goldsmiths, the fauna of conifers is relatively poor in species. Each species prefers one or more closely related tree species and populates a certain part of the tree trunk, branches or roots. Thus, most of the small Antaxia (p. Anthaxia) inhabits the branches and the top of the trunks, and dicerci (p. Dicerca) settle in the lower part of the trees.

Many species of goldfish are very active and attack relatively healthy trees, populating them earlier than longhorn beetles and bark beetles. For their reproduction, they choose sparse, well-warmed plantings that grow in xerophilic conditions, first of all, forest edges, wings, undercuts, groups of seed plants in felling areas, shelter belts and plantings without lateral shading of the second layer and undergrowth.

On conifers, the most common and harmful species are blue pine goldfish, six-point larch, goldfish, four-point spruce goldfish, conflagration goldfish, ribbed bronze goldfish, juniper goldfish.

Blue Pine Goldfish(Phaenops cyanea F.). Beetle 8 - 11 mm, with a flat elongated body. The coloration of the lower part of the body is green, the upper is blue-green or dark blue with a metallic sheen (Fig. 111) Summer in June - July. The female lays eggs in the cracks in the bark. After three to five days, the larvae hatch. They gnaw through long, winding passages that ring a tree, and hibernate in the thickness of the bark, curled up into a horseshoe.

The larvae pupate in May next year. The pupal phase lasts 10 - 15 days, generation is one-year.

Zlatka is the first to inhabit weakened, but still quite viable pines with a thinned crown and yellowing tips of needles, at the age of 20-80 years. The settlement begins from the southern side of the tree from a height of 1 - 1.5 m and covers the entire middle part of the trunk to the point of attachment of the crown. She prefers sparse dry pine forests. They multiply especially intensively in foci of root sponges and in fires, in pine crops after a two-year spring drought.

Goldfish larvae are actively exterminated by small variegated woodpecker and pikas, entomophages do not play a large role in fluctuations in numbers. An admixture of spruce in pine forests sharply reduces the number of goldfish.

Larch six-point goldfish(Phaenops guttulata Gelb.). Beetle 7-11.5 mm long, elongated-oval, black, with a bronze sheen; elytra with three pairs of light yellow spots. Summer is in June - July. The female lays eggs in the cracks in the bark of Siberian and Daurian larch trees. The larvae hibernate under the bark and pupate in May. Young beetles feed on larch needles.

Zlatka settles on relatively weak, still viable trees of different ages. Inhabits the warmest part of the tree from a height of 3 - 5 m. Prefers sparse plantations damaged by pine insects, burning, logging areas. Distributed throughout the natural range of Siberian and Daurian larch.

Zlatka of conflagrations(Melanophila acuminata Deg.). The beetle is 6.5 - 13 mm long. Monochromatic coal-black, elongated, wedge-shaped tapering posteriorly. Summer is in June - July. Females lay their eggs in cracks in the bark in the lower and middle parts of the trunks. The larvae sharpen long passages, like in the previous species, hibernate and pupate in the wood. Generation is one-year. Occurs on burnt-out areas. Prefers middle-aged spruce trees, less often pine and other conifers. In Siberia, it often populates birch (Rozhkov, 1966). The species is very light and thermophilic, widespread throughout the forest zone.

Ribbed Bronze Goldfish(Chrysobothris chrysostigma L.). It is distributed in the forest zone and in its way of life is very similar to the previous species.

Four-point goldfish(Anthaxia quadripunctata L.). The beetle is 4 - 7 mm long, matte, black-bronze, with four pits on the chest shield. Summer in June, females lay eggs in cracks in the bark of middle-aged spruces, in the middle and lower part of the trunk, mainly on the southern or unshaded side. The larvae grind long, winding, gradually widening with sharp edges flat tunnels filled with variegated brown flour under the bark, and hibernate in them. Before pupation, they go deeper into the wood. Young beetles undergo additional feeding on yellow flowers of dandelion and other Asteraceae. Generation is one-year.

Distributed throughout the forest zone, in the forest-steppe there is a variety of this goldfish that damages pine.

Juniper goldfish(Anthaxia conradti Sem.). The beetle is 4 - 7 mm long, dark bronze, wide, flat. The flight is in April - May, often dragging on until July (Makhnovsky, 1966). The female lays eggs in cracks and under the scales of the bark of branches on weakened trees and felling remains of juniper. The larvae gnaw long, winding, gradually widening and weakly touching wood passages. They hibernate and turn into pupae in the spring. Then after a decade into beetles. Young beetles feed on dandelion flowers, then rose hips. Generation is one-year (according to Makhnovsky, on growing trees - two-year).

Juniper goldfinch prefers sparse, well-lit places, is light-loving and thermophilic, and is distributed throughout the entire range of juniper.

There are many species of goldsmiths on deciduous trees. The most common ones are described below.

Green narrow-bodied goldfish(Agrilus viridis L.) (Fig. 112). The beetle is 6 - 9 mm long, with a narrow, more convex body below, metallic green or blue. Flight of beetles in June. Females lay eggs in heaps on the smooth bark of trunks and branches. One pile contains 7 - 11, maximum 20 eggs. The female fills the eggs with secretions from the accessory gonads, as a result of which convex white shields with a diameter of 2 - 3.5 mm are formed on the trunks.

Coming out of the eggs, the larvae gnaw under the bark and lay tunnels clogged with boring flour. Each larva makes an independent move, but depending on the state of the tree, the passages of the larvae either freely diverge to the sides, or form an oval ball located along the trunk or branch (Fig. 113). In autumn, the larvae go deep into the surface layers of wood and arrange pupal cradles in which they hibernate. In the spring, the larvae pupate, and soon young beetles appear, which undergo additional feeding on the leaves of the trees. Everywhere generation is one-year.

The foci are formed in sparse young plantations on poor and dry soils, along the southern edges, in openwork shelter belts, etc.

The greatest harm to the goldfish brings poplars, birches and maples, and in the west - beech. In appearance and lifestyle, some other narrow-bodied goldsmiths are very similar to the green narrow-bodied goldfish.

All narrow-bodied golden beetles fly in June, hibernate in the larval phase, have a one-year generation, beetles feed on the leaves of the trees on which the offspring live. They populate young trees or the tops and branches of older ones, are light-requiring and prefer sparse coppice stands, upset by felling, "backstage" and southern edges, narrow shelter belts of openwork construction, planting without lateral shading. Narrow-bodied goldfish are dangerous physiological pests of steppe forests, especially during drought years, and measures to combat them are rather difficult.

Narrow-bodied goldsmiths differ in egg-laying. Like the green narrow-bodied goldfish, the narrow-bodied hornbeam goldfish (Agrilus olivicolor Ksw.), Widespread in the hornbeam growing areas, the narrow-bodied goldfish (A. betuleti Rtrb.), Which harms young birch trees in the shelter belts and other-steppe zones, lays eggs under the cap.

In contrast to these species, narrow-bodied goldsmiths that settle on oak lay eggs in cracks in the bark one at a time, usually at a short distance from each other. They are the most dangerous pests of oak forests in the steppe and forest-steppe zones during dry climatic periods. Widespread in oak forests are the silky narrow-bodied goldfish (Agrilus hastulifer Rtrb.), The summit narrow-bodied oak goldfish (A. angustulus 111.), the two-spotted narrow-bodied oak goldfish (A. biguttatus F.), the elongated small-bodied goldfish (A. sulcollis) and narrow-bodied oak goldfish (A. obscuricollis Ksw.).

These goldsmiths prefer young and middle-aged coppice oaks, and in the old ones they inhabit only thick branches and the top of the trunk. The exception is the two-spotted goldfish, the larvae of which live under the thick bark of fresh stumps and in the butt of living old oak trees no higher than 2 - 5 m.

All of them have a one-year generation (only in the two-spotted golden beetle in the northern regions it is two-year), feed on oak leaves in the beetle phase (Fig. 114), fly well and are distinguished by exceptional light and thermophilicity.

Bronze oak gold(Chrysobothris affinis Fobr.) Is less active than narrow-bodied golden beetles, inhabits already strongly weakened oaks, mainly windfall, windbreak and forest products together with variegated barbel. Flies in June. Lays eggs in cracks in the thick bark. The larvae sharpen long longitudinal passages, clogged with drill meal, and then go deeper into the surface layers of the wood, where they hibernate, and pupate in the spring. Generation is one-year, in the forest zone it is two-year.

Aspen goldfish(Poecilonota variolosa Payk.). Damages aspen and poplars in the southeast. Fly in May - June, two-year generation.

Poplar spotted goldfish(Melanophila picta Pall.).

A dangerous pest of poplars in Central Asia, Kazakhstan, the Caucasus and the southeast of the European part of the USSR (Fig. 115). Years of beetles in May - June (in the southern regions of Central Asia from the end of April). During additional feeding, they eat the edges of leaves, petioles and young shoots. The female lays eggs in cracks and depressions of the bark one at a time, less often two or three in one place. Egg development lasts 8 to 10 days. The larvae lay winding passages under the bark filled with boring meal (the length of the passages is 12-15 cm). On thin stems, the passages are collected in balls. In autumn, the larvae go shallowly into the wood, arrange a pupal cradle and hibernate in it, and pupate in the spring. Generation is one-year.

The species is very plastic, light and heat-loving, active. It is found wherever poplars grow, attacks trees of all ages, windblows, forest products and stumps. Particularly harmful to young poplars on plantations and plantings, damages the lower part of the trunks and cuttings.

Control measures: in plantations infected with goldfish, sanitary felling and felling of freshly populated trees should be carried out, followed by their chemical treatment. In the production of crops - treatment of cuttings with slurry with hexachlorane, on plantations, coating and spraying of stems with 2 - 4% working emulsion of 16% concentrate of gamma isomer of hexachlorane.

In the conditions of Central Asia, agrotechnical measures (loosening the soil, caring for cuttings) play an important role, sharply reducing the harmful activity of the goldfish.

A number of Capnodis species are serious pests of tree species (especially fruit species) in Central Asia, Kazakhstan, the steppe zone of the RSFSR, the Caucasus and Crimea. These large goldfish fly from April almost all summer. Eggs are laid in the soil near the roots or directly on the roots and at the base of the trunks. The larvae damage the roots and the lower part of the trunks, grinding out long, wide passages, often up to 2 m long. They live for two to three years. Generation is two- and four-year. Beetles hibernate under fallen leaves and in heaps of garbage. During additional feeding, they do great harm by gnawing cuttings and shoots; leaves fall to the soil, often covering it with a continuous layer.

Resin elephants (Pissodes)

Resin elephants (Pissodes) have a rounded rostrum, approximately in the middle of which antennae are attached. It is as long as the pronotum, slightly curved; antennal groove straight, going to lower edge of eyes. Shoulders of elytra not protruding, tibiae with a hook at the end. Scutellum is round, large, with light scales. Elytra in spots formed by scales. The larvae are white with a yellow-brown head, blind, legless, curved. Several species of beetles belong to this genus, which cause great harm to coniferous plantations at the age of 15 - 40 years, and sometimes even older. They subtly react to the slightest weakening of the tree and settle on various parts of the trunk. The female lays several eggs in the bark. The larvae gnaw under the bark the wriggling and gradually expanding in different directions from the place of oviposition. On thin stems, the direction of the passages is longitudinal, and on thicker ones, they diverge star-like. A typical course of the resin is shown in Fig. 116.

The larvae pupate in the sapwood, where they make an oblong depression (cradle), which is covered with small shavings. Pupation usually occurs at the end of summer, and soon a beetle emerges from the pupa and gnaws at a delineated round flight hole. Beetles usually hibernate in the forest floor and under the bark of old stumps, and in spring they begin to reproduce. They undergo additional feeding on the bast in the area of ​​the thin bark of trees or on young shoots and branches. Generation in all species is one-year.

In the previous chapters, we examined the resinous elephants that harm cones (Pissodes validirostris) and young pine crops (Pissodes notatus).

Older plantings are damaged by the following species.

Pine summit resin(Pissodes piniphilus Hrbst.). Distributed in clean pine plantations for 15 - 40 years. Beetles fly in June - July and lay eggs in 1 - 5 pieces. under the thin bark at the top of the pines. The larvae make winding, gradually widening passages between the bark and the bast. On thicker trees, the passages form a star-shaped figure. The larvae hibernate and pupate in the sapwood in spring. Attacks still viable pine trees, causing them to die off. The outbreaks arise in places of massive snowfall and snow breaks, with intensive thinning of dense stands.

(Pissodes pini L.). It settles in the area of ​​the transitional bark of middle-aged pines (Fig. 116). The lifestyle is the same as that of the previous species. A very common species, it accompanies the blue goldfish, pine bark beetles.

Spruce resin(Pissodes harcyniae Hrbst.). It attacks apparently healthy trees and is a constant companion of tree root diseases (honey fungus, root sponge). Flight of beetles and laying of eggs are very extended (from late May to July). The larvae form typical winding star-shaped passages ending in pupal cradles. Pupation in autumn or spring. Young beetles additionally feed on the upper part of the trunks, cause resinification and greatly weaken trees.

Fir resin(Pissodes piceae 111.). Damages Caucasian and White Fir. Flight in May, early June, extended. Laying eggs in areas with damaged bark. Larvae and beetles hibernate. Prefers thick bark area. The beetles pass additional food on fir undergrowth, eating out areas in the bark.

Larch resin(Pissodes insignitus Boh.). Damages all types of larch trees in Siberia. Generation is one-year.

Hymenoptera

Horn-tails (Siricidae)

Horn-tails have a long cylindrical body, pointed behind, in females with a prominent, sometimes long ovipositor. The larvae are whitish, cylindrical, slightly S-curved, flattened on the ventral side, with three pairs of rudimentary thoracic legs and with a sharp stepped process at the posterior end of the abdomen. With the help of the ovipositor, the female drills the bark and lays eggs 1 - 3 pcs. in one place in a strip along the trunk. The larvae make round passages in the wood, tightly clogged with dusty drill meal. Trees damaged by horntail can be found in round, typical flight holes. Horn-tails fly from June to September. Generation is one- and two-year. Additional food does not pass.

All horn-tails cause technical harm; in addition, many species are very active and can attack apparently healthy trees, choosing trunks with mechanical damage. The hidden way of life makes them inaccessible for study, and therefore the biology of a number of species is still insufficiently known.

The most common species on conifers are large coniferous (Urocerus gigas L.), blue (Sirex juvencus F.), purple (S. noctilio F.), black-blue (S. ermak Sem.) And black (Xeris spectrum L. ) horn-tails.

Large coniferous horntail(Fig. 117) damages spruce and pine, and in the forests of Siberia - spruce, fir, Siberian cedar and larch. Generation is two-year, in the south it can be one-year. The species is ecologically plastic, settles on weakened trees in combination with barbel and goldfish.

Blue, purple and black horn-tails widespread in the forests of the USSR. They damage pine, spruce, fir, less often larch. Midsummer flight, one- and two-year generation.

Black and blue horntail- a typical inhabitant of the Siberian taiga. Flying in July - August, two-year generation. Damages all conifers, hygrophilous (Stroganova, 1968).

On deciduous species, the biology of horntail has not been studied enough. Therefore, their importance as active stem and technical pests is often underestimated. The most famous is the birch horntail (Tremex fuscicornis L.). It is the largest species living on deciduous trees (body length 30 - 40 mm). It flies in August - September, the larva makes complex moves in the wood and pupates near the surface. Generation is two-year. Often inhabits birch together with green narrow-bodied goldfish. The species is ecologically plastic, its foci are found in field-protective forest belts, in swampy birch forests, in depressions of sand blowing, etc. In addition to birch, it occasionally damages willow, aspen and elm.

Deciduous species are also damaged by a number of Xiphydriidae - hymenoptera very close to horn-tails and usually bearing the same name. Among them, alder and oak xyphidria are especially widespread.

Alder xifidria(Xiphydria camelus L.). It damages a number of deciduous species, but especially harms middle-aged alder stands, often forming large foci. Summer is in June - July, generation is one-year.

Oak xyphidria(X. longicoltis Geoffr.). Damages oak; lifestyle as in the previous species.

Lepidoptera

Tree trunks are damaged by butterflies belonging to the families of woodworm and glass moths.

Woodworms (Cossidae)

Large, densely haired nocturnal butterflies.

Corrosive arboreal(Zeuzera pyrina L.). The butterfly has a wingspan of 40 - 70 mm, satin-white with numerous angular bluish-black spots (Fig. 118). The flight of butterflies begins in the second half of June and lasts until mid-August. Butterflies are not very mobile (especially females), they hardly fly and do not feed. There are usually more females in nature than males. Females lay elliptical eggs, first yellow, then orange one at the tops of young shoots, in the axils of the leaves, at the leaf scars and buds. The fertility of one female is on average 1000 eggs, sometimes 1140 and even 2280 eggs. The development of a caterpillar in an egg lasts 12-15 days (Anfinnikov, 1961).

After leaving the egg, the young caterpillar is drilled into the leaf petiole, which causes the damaged leaves to dry out and fall off prematurely. After 7 - 10 days, young caterpillars leave the leaves, get to the shoots of the last year, penetrate inside them and grind through the passages, feeding on the core. Before the onset of low temperatures, the caterpillars have time to molt and move to the shoots of previous years, where they become clogged with a wormhole and hibernate. In the second year, in addition to vertical tracks, caterpillars make horizontal tracks, which cut the vessels and weaken the tree. As the caterpillars grow, they continue to change their courses and descend lower and lower in the tree. In autumn, they clog up in the passages laid in the middle and lower parts of the tree, and hibernate a second time. In the spring of the third calendar year, the caterpillars no longer change their course, but only expand the inlet in it and complete their development. The course consists of a rather wide irregularly shaped cavity between the wood and bark, with a hole in the latter, and a channel extending upward, first bending, and then straight, up to 15 - 20 cm long.

The adult caterpillar is 16-legged, yellowish-white, on each segment of the body with a row of black dots bearing one hair. The head is large, dark brown, body length 50 - 60 mm.

At the end of May - June, the caterpillar pupates without a cocoon in the upper part of the passage, where it hibernated. Pupa yellowish-brown. There is a short horn on the head between the eyes, apex facing forward. Its development lasts 6-10 days. Before the butterfly exits, the pupa goes down and protrudes halfway from the entrance hole.

The generation of arboreal trees is two-year, with distinct flight years. They most often fall on odd years. In urban plantings, there are often no clearly defined flight years.

Woodwood is a corrosive polyphagous plant that damages more than 70 tree species, half of which are widespread in the plantations of the European part of the USSR. Ash trees are most damaged, then elm, less often oak; in a number of cities, mountain ash, ash-leaved maple, linden, white acacia are heavily infected, and among fruit trees - apple and pear. Of the ash trees, common ash is damaged the most, and green ash is the least damaged.

The intensity of tree species infestation by arboretum is inversely related to the energy of their growth. Therefore, plantings and individual trees, characterized by poor growth, lack of care, and mechanical damage, are especially strongly infected. In forest conditions, the intensity of infection increases sharply after the culmination of the current growth (by the age of 15 - 25).

The tree forest prefers illuminated and warmed areas, therefore, the infestation increases towards the southern and western edges, on wide streets, with a rare standing of trees. The plantings with good lateral shading, dense, with the presence of a second tier or created according to the tree-shrub type are the least damaged. Plantings and trees of coppice origin are always damaged more than those that originated from seeds. Woodwood spreads with planting material, sometimes with wood.

Woodpecker caterpillars are exterminated by woodpeckers, and eggs are exterminated by the great tit. Entomophages are not of great importance in fluctuations in the abundance of arboreal trees. The centers of its mass reproduction in the steppe forests of the southeast of the European part of the USSR are distributed over large areas and are quite stable.

Control measures are carried out in a complex. To eliminate foci of mass distribution of woody trees and growing healthy plantations, it is necessary to carry out a set of measures. It consists of sanitary felling, measures to create new sustainable plantings, quarantine and chemical control measures.

The sampling of individual trees inhabited by corrosive arboretum should be carried out in slightly infested stands in order to achieve the localization of the emerging foci. Selective sanitary cuttings are carried out in plantations with an average degree of population, subject to their normal closeness. Plantations with a completeness of no more than 0.6 and a degree of infestation of at least 50% are allocated for clear sanitary felling. These fellings should be linked to the flight years and the timing of the development of the tree.

All fellings should be accompanied by careful destruction of small branches that may be inhabited at this time by tree caterpillars. It is recommended to perform thinning in tree-infected plantations once every four years, during flight years, while observing the same conditions as for sanitary felling.

When creating new plantations resistant to arborealis, it is recommended:

plantations with the participation of ash to create according to the tree-shrub type with the introduction of ash no more than 10% of the composition, reducing this amount in the worst growth conditions, up to complete exclusion from the composition; common ash and fluffy are best replaced with green ash, and birch bark and elm - with small-leaved elm;

new plantings in the immediate vicinity of infected plantings should be carried out without ash, introducing oak, field maple and other resistant species into the plantings.

Planting material in nurseries must be checked before removal and, in case of detection of seedlings infected with tree caterpillars, immediately destroy them. Nurseries should be laid no closer than 500 m from infected plantings, especially ash trees.

In all plantations where it is possible to carry out individual tree care, it is advisable to use dichloroethane and hexachlorane for introduction into the final passages of arboreal trees, usually located in the lower part of the trunks. Chemicals are injected into the passages using a bent-tipped rubber bulb or wet swabs. The openings of the passages for a more effective effect of the chemicals must be covered with clay or, even better, cemented. Consumption rates - 0.5 g per one stroke. Chemicals should be injected into the openings of the passages in August - September of the interflight year or in May of the flying year, when infected trees are clearly visible by the accumulation of feces near the base of the trunks and fresh active passages are easily distinguishable.

On large areas, it is possible to apply aerial-chemical spraying during the flight of butterflies and against young caterpillars using aqueous solutions concentrated emulsions of hexachlorane.

Odorous woodworm(Cossus cossus L.). The butterfly has a wingspan of 80 - 85 mm. Both pairs of wings are brownish-gray, dotted with numerous transverse black stripes. Antennae comb-like (Fig. 119).

The flight of butterflies in the forest-steppe begins in the second decade of June and lasts for about two weeks. In the forest zone, it is more extended. Butterflies fly in the evening. Weather conditions do not significantly affect their flight. The female lays eggs in bark cracks in heaps of 20 - 70 eggs. (fluctuations 4 - 228 pcs.). Fertility of the female is about 1000 eggs (fluctuations 237-1350 pcs.). Eggs are laid by the female mainly in the first three to four days. The eggs laid in the last days are small, weighing 30% less than those laid on the first day (Nasonova, 1960). The egg phase lasts 10 to 12 days. For the first two or three days, the caterpillars sit under the shells of the eggs, then they bite under the bark and all together gnaw a common surface course of an irregular shape. Caterpillars throw red-brown feces, which are easy to detect infection.

Caterpillars 16-legged, 100 - 120 mm long, with black plaques on the body, bearing hairs; the head is dark brown, shiny. The body color of caterpillars changes throughout life. Newly hatched caterpillars are pink, then they become maroon, and before pupation they change color again to pink and finally acquire a cream color.

In the first year of development, the caterpillars have time to fade four to five times. They hibernate in family passages, and the next year they disperse and are separately stuck into the wood, where they make wide, mainly longitudinal passages. In total, caterpillars have eight instars, and their development lasts 22 months. In the fall of the second year, many caterpillars abandon their tunnels and crawl in search of a place to pupate.

Pupation occurs in the third year in the second decade of May - early June. Caterpillars pupate in a dense silky cocoon in the bud, old stumps and at the base of the trunks of the trees in which they lived. The pupal phase lasts about a month. Generation is two-year.

Woodworm inhabits mainly the lower part of the trunks of trees of various deciduous and fruit species: willows, poplars, alder, elm and oak. Small but persistent perennial foci are often formed. The settlement is easily recognizable by the sawdust, sap flowing from the holes and the strong smell of wood vinegar.

Control measures. Sanitary felling and felling of inhabited trees in the fall of the flying year, when the caterpillars hibernate under the bark in common passages. In gardens and urban plantings, you can introduce an emulsion of hexachlorane into the tracks of the caterpillars and cover the tracks with clay.

Aspen woodworm(Cossus terebra F.). Butterflies are similar to the fragrant woodworm, but the general color tone is more gray, and not light brown, like in the previous species. Antennae are comb. The lifestyle of this species is very similar to that of the previous species, but the females lay eggs scattered, two or three eggs in one place, and do not cover them with a brown solidifying liquid. Caterpillars never crawl out of their tunnels, pupate in the tree where they developed, and do not make a cocoon (Zolotarenko, 1959). Generation is not exactly established. This species damages only aspen and poplars and, apparently, is widespread, but its caterpillars are often mistaken for the caterpillars of willow woodworm.

In Central Asia, it is widespread tamarix woodworm(Holcocerus arenicola Stqr.). Caterpillars live in the lower part of the trunks and roots of tamarix, saxaul and other woody plants growing in the desert and tugai forests. On tamarix, the biology of this species is similar to that of other woodworms. There are foci sporadically, but in some cases it can cause great harm to tamarix (Sinadsky, 1960).

Glassworms (Aegeriidae)

Small butterflies with narrow transparent wings, resembling hymenoptera. The hind wings are shorter than the front ones; the scales are concentrated on the veins. The body is rather slender, the abdomen is long, protrudes far beyond the wings, the antennae are fusiform. They fly during the day. Caterpillars are whitish, 16-legged, with a brown head and sparse hairs that are regularly spaced along the body rings. Most species live in the wood of trees, often causing great harm to them. The most widespread are the dark-winged and large poplar glass cases.

Dark-winged glass(Paranthrene tabaniformis Rtt.). The most common and dangerous pest of poplars in the plantings of most cities. The butterfly has a wingspan of 24-28 mm, bluish-black, shiny, with narrow yellow rings on the abdominal segment. The front wings are coffee-brown, and at the base they are transparent with a slightly darker fringe. The hind wings are transparent, glassy (Fig. 120).

The flight begins in the middle zone from the end of June and in July, and in the south at the end of May. Females lay oval-elongated, pitch-black eggs, one or less often several at once on branches and trunks in places of various injuries. Fertility of one female is 200 - 600 eggs. The development of the caterpillar in the egg is 12 - 13 days, and at high temperatures (up to + 30 ° C) it is reduced by two to three times. The caterpillars that emerged from the eggs bite under the bark, where they make separate areas (cavities), and then go deep into the wood up to 4 cm and make longitudinal passages up to 15 - 24 mm long in it. A characteristic feature of the colonization of trees with glass is heaps of brown excrement and drill meal on the trunks at the holes and at the base of the trees.

Young caterpillars are whitish-pink, while adults are white or yellowish. The head and occipital scutellum are brownish brown; the last abdominal segment has two brown spines. Body length 22 - 24 mm. Caterpillars molt five times and have six instars. They live for two calendar years - the first year they winter at the third age in the cavities under the bark, and the second time - at the sixth age in the passages in the wood. Before pupation in the third calendar year in spring, they make a lateral flight below the upper end of the stroke in the wood to the surface of the bark. The caterpillar then pupates at the upper end of its stroke in the wood in a yellowish cocoon. The place of pupation is fenced off by a caterpillar from the rest of the course with a cork of sawdust and cobwebs. The pupal phase lasts 12-14 days. Before the butterfly emerges, the pupa moves along the course with the help of the spines of the abdomen, pushes the thin layer of the bark apart and protrudes outward by about 2/3 of its length.

Pupa is dark yellow or reddish-brown, becoming almost black before the butterfly emerges. Length 15 - 20 mm. Generation is two-year. The glass beetle inhabits trees of all ages, including coppice shoots from the second year of their growth with a thickness of 0.7 cm and more. On young shoots, trunks and branches in places where the pest settles, gall-shaped or one-sided swellings are formed. On trees 10 years and older, the glass can inhabit not only the lower part, but the entire trunk, forming growths along its entire length with flowing brown sap. Inhabiting stumps, it prevents the growth of the growth. Through the tracks of the caterpillars, trees can become infected with fungal and bacterial diseases, and redness appears inside the wood.

Large poplar glass(Aegeria apiformis Cl.) (Fig. 120). The butterfly has a wingspan of 35 - 45 mm, black-brown with lemon-yellow spots and stripes, transparent wings. In appearance it resembles a wasp. The flight begins in the middle zone in July, in the south - in June and lasts about a month. Females lay oval-flattened, brown-colored eggs one at a time or in small heaps on the lower part of tree trunks, on roots and soil. Fertility of one female is 1000-1300 eggs; sometimes reaches 2500 eggs. The development of a caterpillar in an egg lasts two to three weeks.

The caterpillars that emerged from the eggs are stuck under the bark of the roots of the lower part of the tree trunks, where they gnaw out small areas first, and then go deeper into the sapwood and make grooved passages clogged with sawdust. In the butt of the trunks and in thick roots, the passages are irregular, often merging into platforms, and on the roots - longitudinal, sometimes with a deepening of 20-30 cm into the soil. Young caterpillars are pale pink, adults are white or slightly yellowish. The head is reddish-brown. On the tergite of the last segment of the abdomen, there is a small wart with an inconspicuous chitinized scutellum, inclined towards the head. Body length up to 55 mm.

Caterpillars molt seven times and go through eight instars. They usually live for two calendar years, winter in passages, and in the third year in the spring they pupate in a cradle under the bark at the butt neck in a dense cocoon of sawdust and excrement; often - in the soil near the roots. The pupal phase lasts 20 to 25 days. Pupa brown or reddish-brown with a row of spines on the dorsal side of the abdomen. The head and pronotum with a common longitudinal keel-like depression protrude 2/3 out of the flight opening. After the departure of the butterfly, the pupa's skin remains sticking out in the round flight hole. On this basis and the large drill meal protruding from under the bark, it is easy to identify inhabited trees.

Control measures. With glass cases, control measures are mainly of a preventive nature. When creating poplar crops with cuttings or seedlings, it is necessary to carefully reject the planting material, not allowing the specimens inhabited with dark-winged glass to be used, for which it is necessary to reject specimens with bulges and with sawdust. When creating poplar crops, it is desirable to shade from shrubs that prevent settlement. Elderberry introduction is recommended. On plantations and urban plantings, it is necessary to repair plantings, replace poplars with other species, select resistant species poplars, etc. To destroy the emerging butterflies at the end of May - June, areas of the tree trunk are coated with paste of the following composition: 40 parts of manure, 50 parts of clay and 10 parts of water. In nurseries, with valuable plantings - cutting and destruction of populated parts of plants, crushing caterpillars with a wire in the tunnels, covering damaged areas with cement, etc. Chemical treatment of valuable crops with systemic insecticides (rogor, phosphamide, Bi-58), as well as chlorophos at 0 , 5 - 1% concentration during the hatching period of larvae and their nutrition in the surface layers of the bark before burrowing into the wood. Protective treatment of trees and stumps before the flight of pests is also possible with a 3-5% emulsion of the gamma isomer HCH (by 16% preparation). When populating up to 30 trees - selective chemical treatment, with a higher population - continuous processing of plantings. Consumption of working fluid for wood processing 0.2 - 0.5 l per tree, mechanized solid - 100 - 300 l / ha. A selection of freshly populated dying trees.

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Lindeman GV Ways of adaptation of bark beetles-sapwood (Coleoptera, Scolytidae) to habitat on slightly weakened trees.- Ecology, 1978, No. 6.

Lozovoy D. A. Harmful insects of park and forest plantations in Georgia. Tbilisi, 1965.

Lurie, M.A., Groups of spruce stem pests in the southern taiga subzone of the European part of the USSR. 10.M., 1965.

Mamaev B.M.Biology of wood destroying insects.- Vses. in-t scientific. and tech. information, ser. Results of Science and Technology, vol. 3, - Entomology, M., 1977.

Maslov A.D. Pests of elm breeds and measures to combat them. M., 1970.

Maslov A.D., Kuteev F.S., Pribylova M.V. Forest stem pests. M., 1973.

Makhnovsky IK Pests of mountain forests and their control. M., 1966.

Mozolevskaya EG Features of the development of forage resources by xylophagous insects. - Lesovedenie, 1979, No. 6.

Ozols G.E., Bichevkis M. Ya. Study of attractants of the bark beetle-typographer Ips typographic (Col. Ipidae) in the Latvian SSR.- In the book: Protection of conifers in the Latvian SSR. Riga, 1976.

Ogibin B.N.On regulation of population density of Ips typographies (Coleoptera, Ipidae) at preimaginal stages of development. - Zoologist, zh., V. 53, no. 1.M., 1974.

Pavlinov N.P. Large poplar glass - a pest of crops in the Moscow region.- In the book: Forest protection from pests. Pushkino, 1963.

Pavlinov N.P. Big aspen barbel and measures to combat it.- In the book: Protection of forest plantations from pests and diseases. M., 1965.

Pavlinov N.P. Small aspen barbel and control measures .- In the book: Forest protection from pests and diseases. M., 1968.

Petrenko E. S. Insects - pests of the forests of Yakutia. M., 1965.

Smelters NN Woodcutter beetles - wood pests. M. - L. Insects Coleoptera, t. XXI, 1936; v. XXII, 1940; v. XXIII, no. 1, 1958.

Pogorilyak I. M. Bark beetles and biological bases of their control. Uzhgorod, 1973 (in Ukrainian).

Polozhentsev P.A. app. Voronezh. forestry engineering. in-ta, v. XII. Voronezh, 1953.

Prozorov S.S., A large black barbel on Siberian fir, Tr. Siberian. forestry engineering. in-ta, t. XXI, no. 2. Krasnoyarsk, 1958.

Richter A.A. Review of goldsmiths of the European part of the USSR.- Sat. Zoological. in-that Arm. SSR. Yerevan, 1944.

Richter A.A. Zlatki.- Fauna of the USSR, Coleoptera insects, vol. 2.M.-L., 1949, no. 4, 1952.

Rozhkov A.S. Wood and insects. Novosibirsk, 1981.

Rudnev D.F. Big oak barbel in the woods Soviet Union... Kiev, 1957.

Rudnev D.F., Smelyanets V.P., On the nature of resistance of tree plantations to pests, Zoolog, zh., Vol. 48, no. 12.M., 1969.

Stark V. N. Bark beetles. - Fauna of the USSR, Insects Coleoptera, t. 31. M. - L., 1952.

Stroganova V.K. Horntail of Siberia. Novosibirsk, 1968.

Trofimov V.N. Biology of alder horntail in the Khopersky reserve. tr. Moscow forestry engineering. in-ta, no. 90. M., 1976.

Trofimov V.N.Biology of the marble squeaky Saperda scalaris L. (Coleoptera, Cerambycidae) according to observations in the Khopersky reserve. - In the book: Ecology and forest protection, vol. 5.L., 1980.

Trofimov V.N.

Turundaevskaya T.M. M., 1981.

Shevyrev I. Ya.Middle of bark beetles, 4th ed. / Ed. P.G. Troshanin. M., 1969.

Yanovskiy V.M.The role of entomophages in the dynamics of the abundance of the large larch bark beetle.- In the book: Ecology of populations of forest animals in Siberia. Novosibirsk, 1974.

Pine wood has an average density and rather high strength. It is resistant to rotting and fungal attack. In the furniture industry, this wood is especially valuable as a result of the small number of knots and the slight change in diameter along the length of the trunk. Pine wood has high strength, which makes it possible to use it for the construction of various structures.

Pine board is the most common building material. Not only due to the large areas of forests, but also as a result of its excellent qualities... This material is used both in the construction of houses and in the construction of ships.

Pine timber is a very popular lumber today. It is characterized by a rather attractive appearance. It has excellent heat and sound insulating properties, as well as fairly high strength, but at the same time low weight.

The range of furniture made from pine is quite wide: hallway sets, bedroom and kitchen sets, tables and chairs, office furniture. This is not surprising, because pine wood furniture is beautiful, practical and durable.

Mighty, tall and slender pines were an excellent base for the construction of powerful ships that Russia is known for. Hence the name - ship pine. Pine forests in the old days were called "ship groves", and the ships themselves - "floating pines". In the groves of the ship, pines grow up to 40 m and almost 50 cm in diameter. In the past, shipbuilders used pine resin extensively for impregnating ropes, sails, and pitching grooves on ships and boats.

Scopes of pine

Pine has the most active resin apparatus among the conifers of the taiga zone. Therefore, it is widely used for the lifetime production of tree resin - resin - by tapping.

In recent decades, the production of pneumatic resin, that is, rosin and extraction turpentine (somewhat different in composition from gum turpentine), from pine stumps remaining in the clearings has been expanding.

Pine is the main object of the logging, woodworking industry, since pine wood is widely used in construction, furniture, packaging and many other industries, in wood chemistry for hydrolysis and cellulose production.

Pine releases a lot of resinous substances into the air, which makes it one of the most active phytoncidal species in our forests.

The use of pine wood is very diverse. It is used in construction as constructional and finishing materials, mechanical engineering, furniture production, railway transport, container production, for securing mine workings, etc. It is widely used as a raw material for chemical processing in order to obtain cellulose, fodder yeast. Resin is extracted from pine, pine needles are used to obtain biologically active substances.

Scientific classification		Physical properties
Domain:	Eukaryotes	Average density:	520 kg / m³
Kingdom:	Plants	Density limits:	300-860 kg / m³
Department:	Conifers	Longitudinal shrinkage:	0,4 %
Class:	Conifers (Pinopsida Burnett, 1835)	Radial shrinkage:	4 %
Order:	Pine	Tangential shrinkage:	7,7 %
Family:	Pine	Radial swelling:	0,19 %
Genus:	Tangential swelling:	0,36 %
International scientific name		Bending strength:	80 N / mm²
Pinus L., 1753		Compressive strength:	45 N / mm²
Typical view		Tensile strength:	100 N / mm²
Pinus sylvestris- Scots pine		Fuel properties
		4.4 kWh / kg

Species and types of pine

Ducampopinus	Strobus	Pinus
Pinus aristata Pinus balfouriana Pinus bungeana Pinus cembroides Pinus edulis Pinus gerardiana Pinus krempfii Pinus longaeva Pinus monophylla	Pinus amamiana Pinus armandii Pinus ayacahuite Pinus bhutanica Pinus cembra Pinus fenzeliana Pinus flexilis Pinus koraiensis Pinus lambertiana Pinus monticola Pinus morrisonicola Pinus parviflora Pinus peuce Pinus pumila Pinus sibirica Pinus strobiformis Pinus strobus Pinus wallichiana	Pinus albicaulis Pinus bungeana Pinus contorta Pinus coulteri Pinus densiflora Pinus elliottii Pinus halepensis Pinus heldreichii Pinus hwangshanensis Pinus jeffreyi Pinus mugo Pinus nigra Pinus palustris Pinus pinaster Pinus pinea Pinus ponderosa Pinus radiata Pinus rigida Pinus sabineana Pinus sylvestris Pinus tabuliformis Pinus taeda Pinus thunbergii Pinus torreyana Pinus virginiana

Useful tables

The content of various elements in coniferous wood

Standard resistance of pure pine and spruce wood

Resistance type and characteristics of elements under load	MPa (kgf / cm²)
Resistance to static bending R 1:
for elements made of round wood with an unweakened cross-section	16 (160)
for elements with rectangular section (width 14 cm, height - 50 cm)	15 (150)
for the rest of the elements	13 (130)
Resistance to compression R szh and surface compression R p. szh. :
R п.сж. along the grain	13 (130)
in a plane parallel to the direction of fibers R p.w.pl.	1,8 (18)
Compression resistance of the local surface R p.szh. :
across the fibers in the supporting points of the structure	2,4 (24)
in support notches	3 (30)
under metal pads (if the angles of application of force are 90 ... 60º)	4 (40)
Resistance to elongation along the fibers R rast.v. :
for elements with non-weakened cross-section	10 (100)
for elements with a weakened cross-section	8 (80)
Splitting resistance along the fibers R split.v.	2,4 (24)
Resistance to splitting across the fibers R split.p.	1,2 (12)

Pine specifications

Characteristic	Meaning
Density	513kg / m3
Density when freshly cut	625 kg / m3
Stiffness in the freshly cut state, kg / cm2	79
Dry hardness, kg / cm2	109
Specific gravity	0,51
Static bending strength, MPa	71,8
Compressive strength along fibers, MPa	34,8
Ultimate tensile strength along fibers, MPa	84,1
Shearing strength along fibers, MPa:
radially	6,2
in tangential direction	6,4
Hardness, N / kV.mm:
End	23,4
Radial	21,6
Tangential	20,7
Modulus of elasticity at static bending, GPa	8,8
Specific work at impact bending, J / cm3	1,6
Shrinkage,%:
Longitudinal direction	0,4
In tangential direction	6-8
Radially	3-4

Data at 12% humidity; 1 MPa = 1 N / mm2

MOU Sidorovskaya average comprehensive school

Educational research work

"Why does a pine tree die and how to save it"

Completed: Taranov

Kirill Viktorovich,

8th grade student

Head: Goreva

Galina Anatolyevna,

biology teacher

Sidorovskoe 2008

1.Introduction …………………………………………………………………… 3

2. Biology of Scots pine ………………………………………… ... 5

3. The value of pine ………………………………………………………… .8

4. Research methods ………………………………………………… ..9

5.Results of the study …………………………………………… ... 12

6.Discussion and analysis of actual and numerical data ……………………………………………………………………………… 14

7.Conclusions …………………………………………………………………… .16

8. Conclusion and prospects of work ............................................................. 17

9.Literature …………………………………………………………… ... 18

Introduction.

purpose of work: to draw public attention to the fact of the death of pine forests.

Work tasks:

1. to study the biology of Scots pine, to determine its value

2.Visually assess the condition of the pine forest near the village of Venyaekha

3. to conduct a statistical study of the affected pine needles according to the methodology

4. to propose methods to prevent the death of Scots pine.

Problems.

I was born and raised in the village. Sidorovskoe. From the old residents I know that our places were famous for their rich mushroom pine forests. But where are they now? I know that the pine forest near the village of Venyaekha is a natural monument of the Kostroma region. And what? This forest is becoming sparse, many pines are drying up on the vine, others are half reddened. Needles are falling ...

When burning fuel in large quantities ah, a huge amount of gases are emitted into the atmosphere. Some of them - sulfurous and nitrogenous gases - under the influence of ultraviolet rays and for other reasons turn into acids. Acidified atmospheric moisture in the form of rain, snow or fog falls to the ground. The wind drives acidified clouds over long distances, and acid rain falls on fields and forests, very far from sources of pollution. Acid rain, getting into the soil, on plants and in water bodies, affects soil-forming organisms, agricultural crops, forests, inhabitants of land and water bodies.

Sometimes in the garden you can see drooping, with brown spots completely brown leaves of tomatoes, cucumbers or other plants. These are the consequences of acid precipitation. If, after the rain, your clothes or umbrella are in small burnt spots, this is the action of acid rain.

In European countries acid rain more than 50% of coniferous forests are damaged (70% in Germany). In our country, the area of ​​significant damage by acid precipitation is several tens of millions of hectares.

Every year our school conducts environmental research, including a study of the condition of pine needles in the forest near the village of Venyaekha. It is held annually by the 8th grade. Research takes place at the end of May, starting in 2003. Thus, we have accumulated material for 5 years. I decided to summarize the results obtained, identify the statistical patterns of this phenomenon, establish the reasons, and find ways to stop this process.

Thus:

place of work -- pine forest near the village of Venyaeha

terms of work-- the end of May

duration of work-- 6 years ()

Pine forest near the village of Venyaekha is a natural monument of the Kostroma region. 25.01.08 g.

Scots pine biology.

The generic name is from the Latin pin - rock, mountain, Latin sylvestris - forest from sylva - forest.

By the pine ancient history... She appeared on Earth 150 million years ago. During this time, the face of the planet has repeatedly changed: glaciers advanced and retreated, many species of plants and animals were born and disappeared, and their contemporary - the pine - overcame time, caught its roots in the earth and survived to this day.

On the shores of the Baltic Sea, amber is found - amazingly beautiful petrified resin of ancient pines.

Gold ingots of petrified resin, polished by the sea, are found in many places, but it is the Baltic countries that are considered the amber region. Amber often contains "preserved" in it

Young pine trees at the edge of the forest. 01/25/08

insects that lived in those distant times. Such amber is especially appreciated.

Scots pine is an evergreen slender coniferous tree, reaching 40 m in height, 1.5 m in diameter, with whorled branches. The bark of the tree is red-brown, brown-yellow to the top, fissured, thinly peeling. Young branches are glabrous, greenish, then gray-brown; buds 6-12 mm long, sharp, reddish-brown, ovate-conical, resinous, located at the top of the main shoot and lateral branches. The lateral buds are collected in a whorl surrounding the larger central bud.

All pine wood is penetrated by numerous large resin passages stretching in the vertical direction and communicating with each other by horizontal passages lying in the core rays. From natural cracks in the bark and artificial cuts, resin flows out, filling the damage caused, which is its biological significance. The resin flowing out of the wound is called resin (from the words “to heal”, “to heal”).

Root system with a deep main root.

Leaves (needles) are gray-green, arranged in pairs, rigid, semi-cylindrical, pointed, 5-7 cm long, 2 mm wide, located on the tops of shortened shoots.

Gray-yellow anther (male) cones smaller than a pea develop in spring at the base of young long shoots, in the axils of the covering leaves, and quickly die off. At the ends of young shoots of the same trees, reddish oval female cones appear, 5-6 mm long and 4 mm wide, on short legs, consisting of cover scales, in the axils of which seed scales with ovules sit. After fertilization, female cones grow, reaching 2.5-7 cm in length and 2-3 cm in width. In the first year they are green, in the second they become lignified and brown. Seeds 3-4 mm long, blackish or grayish, oblong-ovate with a wing 3 times as long as the seed. It blooms in May and is pollinated by the wind. Seed cones mature in the second year.

Pine is one of the most common tree species in the forest and forest-steppe zones of the European part of Russia, Siberia, Northern Kazakhstan, Ukraine, and is less common in the Far East. Grows on sandy and sandy loam soils and raised peat bogs.

Description of the plant. This is an evergreen coniferous tree of the pine family, reaching a height of 40 m. The bark is red-brown, yellowish on the branches, flaking. The buds are oblong-ovate, pointed, 6-12 cm long, resinous, surrounded by triangular-lanceolate scales with a transparent film edge. The needles are arranged in pairs, gray-green, somewhat curved, tough, 4-7 cm long, preserved on the shoots for 2-3 years. Male cones are numerous, yellow, collected at the base of the shoots of the current year, female-reddish, solitary or sessile, 2-3 on short legs bent downwards. After fertilization, the cones grow, stiffen, ripen within 18 months. Seeds are oblong-ovate, 3-4 mm long, with a wing 3 times longer than the seed.

Pine is characterized by great morphological variability and forms a large number of forms. Grows quickly, especially when young

age (up to 30-40 years old). The growth in height in favorable soil and climatic conditions reaches 70-80 cm per year. Scots pine lives up to 350-400 years. It blooms in May-June, the seeds ripen in the second year. In medicine, buds (shortened apical shoots), sap and needles of Scots pine are used. Habitat. Spreading. Pine is one of the main forest-forming species in our country. Pine forests cover an area of ​​about 120 million hectares. It grows on sandy, sandy loam, podzolic, soddy, chernozem-like, gley and peat-bog soils. It also occurs on gravelly soils, limestones, chalk and rocky outcrops. Due to its wide ecological range, it is distributed from the forest-tundra to the steppe zone. It rises to an altitude of 1500 m above sea level in Altai and up to 1800 m in the Sayan Mountains. Photophilous, frost-resistant, drought-resistant. In favorable conditions, pine is a tree of the first size, it forms plantations of the highest bonitet class; with excessive moisture, on peat-gley soils, on very dry hilly dune or on rocky outcrops - this is a twisted, knotty tree, the height of which at 100 years of age does not exceed 5 m.In the mountains it sometimes takes an etlanic shape

The value of Scots pine.

1. Pine is a valuable wood used in various industries.

2. Pine tapping is being carried out on a large scale.

3. Rosin and turpentine are obtained from the resin extracted from pine.

4. Pine resin and stumps are used to obtain turpentine and tar.

5. Tannins are obtained from pine bark, pine oil and vitamin C are obtained from needles.

6. Pine is widely used in steppe and field-protective afforestation, it is the main species in the creation of forest crops on the sands.

7. Pine forests are of great water protection and water regulation importance.

8. Pine forests perform important sanitary and hygienic functions, since pine releases phytoncides that protect the air from pathogens.

Research methodology.

Bioindication of air pollution based on pine conditions

It is believed that for the conditions of the forest belt of Russia, pine forests are most sensitive to air pollution. This determines the choice of pine as the most important indicator anthropogenic influence, which is currently accepted as the "standard of biodiagnostics". Morphological and anatomical changes, as well as the lifespan of needles, are informative for technogenic pollution. With chronic pollution of forests with sulfur dioxide, damage and premature fall of pine needles are observed. In the zone of technogenic pollution, there is a decrease in the weight of needles by 30-60% in comparison with the control plots (18%).

Key sites for monitoring air pollution can have a large area (for example, 1 ha) and are selected in a forest massif homogeneous in terms of species composition.

Determination of the condition of Scots pine needles for assessing atmospheric pollution

In unpolluted forest ecosystems, the bulk of pine needles are healthy, have no damage, and only a small part of the needles have light green spots and necrotic points of microscopic sizes, evenly scattered over the entire surface. In a polluted atmosphere, damage appears and the lifespan of pine needles decreases.

The figure shows various options for the state of pine needles.

without spots with black and yellow spots with drying out

The method for indicating the purity of the atmosphere by pine needles is as follows. From several lateral shoots in the middle part of the crown 5-10

pine trees at 15-20 years of age select 200-400 pairs of needles of the second and third years of life.

Selection of Scots pine needles. 28.05.2008.

The needles are taken from trees 15-20 years old.

The collected material is being processed. 28.05.08

The analysis of the needles is carried out in the laboratory. All needles are divided into three parts (intact needles, needles with spots, needles with signs of drying out), and the number of needles in each group is counted. The data is entered into a worksheet.

Research results.

Scotch pine needles.

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Needle damage

total number of needles examined

number of intact needles

% of intact needles

number of needles with spots

% of needles with spots

number of needles with drying out

% needles with desiccation

total number of damaged needles

total% of damaged needles

The graph of the change in the state of needles by years 2

13

The discussion of the results.

The work was carried out strictly according to the method described above. A group of children collected 400 needles (pairs), at the height of human growth, into a new plastic bag. In the laboratory (in the office), the material was analyzed into 3 categories:

Without damage

With stains

With drying out

Then the count is done. We enter the received data into the table. Next, we build graphs and diagrams based on the research data.

Analysis of results.

The number of intact needles was the smallest in 2003 (96 out of 400). In 2004, this figure reached its maximum value (307 out of 400), then began to decline again. In 2007, the number of undamaged green needles increases again (up to 232 out of 400). And this year, 2008, it is again decreasing (to 160 out of 400).

The number of needles with shrinkage was high in 2003 (136 out of 400). In subsequent years, their number declined. But in 2006 their number increased more than 2 times compared to the previous year (164, and 72 in the previous year). In 2007, the number of needles decreases again (56 out of 400). 2008 saw a slight increase in this impression from 400).

The total percentage of damaged needles also changes in waves over the years.

In 2003 and 2006, the number of injured people is high (76% and 63%, respectively).

In 2004, the percentage of damage is minimal (23%).

In 2005 and 2007, the percentage of damage is almost the same (41% and 42%, respectively).

And this year, 2008, this figure rises to 60%.

conclusions

These characteristic damage to the needles, according to the author of the technique, are formed due to an increase in the acidic nature of precipitation.

It is obvious that in 2003 and 2006 the character of precipitation was especially shifted towards the acid side (presumably up to pH = 4).

This could be due to two reasons.

Firstly: the fuel used in those years at the Kostromskaya GRES could contain a high percentage of sulfur.

Secondly: probably in these years (2003 and 2006), the gas-cleaning filters of the enterprise deteriorated their quality, or completely became unusable.

And it is also possible that these two factors act simultaneously.

I believe the following actions are needed to save the pine forest:

1.Use low sulfur fuels.

2. Monitor the quality of gas cleaning filters.

3. Periodically spray over pine forests with substances that create a slightly alkaline environment in order to neutralize possible acid precipitation. Pollination can be done with soda Na 2CO 3. Sodium bicarbonate NaHCO 3 will have a milder effect. But the best option is pollination with wood ash, which contains potash K 2CO 3, since this substance is very close to the forest, non-ferrous (formed as a result of burning wood ), in addition, potassium is a nutrient that strengthens the trunk and root system.

Conclusion and work prospects

1. I studied the biology and significance of Scots pine.

2. I rate the pine forest near the village of Venyaekha today as

satisfactory.

3.I have summarized the statistics of the study of pine needles,

conducted by the children of our school.

4. I made conclusions about the reasons for the death of the pine.

5. By advocating for school work, I have drawn public attention to

the fact of the death of the pine.

6. I proposed measures to save the pine forest.

7.This material can be used in biology, ecology,

chemistry at school, and to inform the public.

Literature

1. "School environmental monitoring"

2. Zverev: textbook for 7-9 grades. general education schools.

4. "Plants from A to Z" M, 1992.

5.http: // www. *****

Review

The topic of work is one of the most relevant today. Pine forests in our area are dying and disappearing. The cause of death is acid precipitation resulting from the combustion of large quantities of fuel at thermal power plants. Acidic precipitation causes premature drying of the needles.

Determining what percentage of the needles are affected is one of the main tasks of research work. The percentage of damage is, according to research, approximately 50 (± 15%), which is typical for the environment of powerful industrial facilities.

Among the educational research works of schoolchildren, I have not met this topic.

The work summarizes research data for 6 years. All statistical data are entered in the table, graphs and diagrams are built on them.

The results were analyzed, conclusions were drawn about the likely causes of the death of the pine, about the possible ways of saving it.

In the work, popular science literature on biology and ecology was used, as well as information resources of the Internet.

This material can be used in the lessons of biology, ecology and chemistry, to inform the public.

Biology teacher: //

During its operation, wood is affected by a number of environmental factors, leading to its aging and destruction. Among them: climatic (UV - radiation, humidity, wind loads, atmospheric oxygen) and biological (fungal infections, insects, bacteria, algae).

The process of destruction is laid down by nature itself to maintain ecological balance, therefore, in natural conditions, wood, over time, decomposes to carbon dioxide and water - the simplest chemical compounds

Changing the properties of wood under
external factors

Effect of drying

During the drying process, raw wood is exposed to steam, heated dry and humid air, high frequency currents of other factors, which ultimately lead to a decrease in the content of free and bound moisture.

Correctly carried out chamber drying of wood gives a material that is quite equivalent to that obtained as a result of atmospheric drying. But if you dry wood in chambers too quickly and at a high temperature, then this can not only lead to cracking and significant residual stresses, but also affect the mechanical properties of the wood.

According to research, with high-temperature drying with a final temperature in the chamber of 105-110 ° C, the drying time is reduced by 1.5-2 times compared to the duration of atmospheric drying, but the strength of pine wood (in boards with a thickness of 30-60 mm) decreases when compressed along the fibers by 0.8-8.7%, radial shearing by 1-12%. The impact strength is reduced by 5-10.5%.

The effect of high temperature drying has been studied by many researchers. Despite the contradictory conclusions caused by different approaches to the interpretation of the research results, these works showed that high-temperature drying leads to a deterioration in the mechanical properties of wood.

The drying time is sharply reduced when using electromagnetic microwave oscillations. However, the degree of specific influence of this factor on the properties of wood has not been fully studied.

Effect of elevated temperatures

An increase in temperature causes a decrease in strength and other physical and mechanical properties of wood. With relatively short exposure to temperatures up to 100 ° C, these changes are usually reversible; they disappear when returning to the initial temperature of the wood.

TsNIIMOD data show that the strength in compression along and across the fibers decreases both with an increase in temperature and with an increase in wood moisture. The simultaneous action of both factors causes b O the greater decrease in strength compared to the total effect of their isolated impact.

With a sufficiently long exposure to elevated temperatures (more than 50 ° C), irreversible residual changes occur in the wood, which depend not only on the temperature level, but also on humidity.

Studies carried out on wood have shown that under the influence of a temperature of 80-100 ° C for 16 days, the compressive strength along the fibers decreases by 5-10%, and the impact strength by 15-30% (the greatest decrease was found for oak, the smallest - for pine). The decrease occurs mainly during the first 2-4 days.

A study of the effects of high temperatures in the range of 80-140 ° C on the mechanical properties of wood showed that the mechanical properties decrease with an increase in temperature, the duration of its exposure and the moisture content of wood.

Influence of low temperatures

Low temperatures have the opposite effect on the strength of wood: the strength of frozen wood increases significantly. Ice provides increased cell wall stability. This explains the increase in the values ​​of ultimate strength in bending, compression and splitting.

Influence of ionizing radiation

Ionizing radiation reduces the strength characteristics of wood. This is explained by the radiolysis (decomposition) of its organic components. However, the use of radioisotopes in the process of non-destructive testing of wood parts and their radiation sterilization (a lethal dose for fungi and insects is about 1 Mrad) does not lead to a decrease in the mechanical properties of the material, because the radiation dose is lower than that which causes noticeable destruction in the wood substance.

Influence of corrosive liquids and gases

Under the influence of acids and alkalis, changes in color and destruction of wood occur. Resinous substances contained in coniferous wood noticeably weaken the negative impact of aggressive environments, therefore, larch products suffer less from their impact and more (two to three times) - deciduous species, especially soft ones. Wood affected by blue is more susceptible to destruction than healthy wood. It goes without saying that the destruction of wood by acids and alkalis leads to a decrease in its strength.

Influence of sea and river water

Tests have shown that after being in river water for 10-30 years, the strength of the wood practically did not change. With a longer exposure to river water, the surface layer (10-15 mm thick) gradually loses strength and begins to collapse. At the same time, the strength behind this surface layer remains within the normal range defined for healthy wood.

If wood has been in water for several hundred years, its properties change greatly. Quantitative and qualitative indicators of these changes depend on the wood species. The most famous are the results of the impact of river water on oak wood. Bog oak changes its color to greenish black or charcoal black, which occurs as a result of the combination of tannins with iron salts. In a state saturated with water, bog oak wood retains its plasticity, but after drying it becomes harder and more brittle than the usual state. The shrinkage of bog oak is 1.5 times greater than usual, which is explained by the shrinking (collapse) of cells with reduced wall thickness, therefore, bog oak wood cracks when drying more than usual. The strength of bog oak in compression and static bending is reduced by 1.5 times.

Prolonged exposure to sea water leads to a noticeable increase in the hardness of larch. During the construction of Venice, about 400 thousand pieces of larch piles were driven in to strengthen the foundations of various structures. Later, some of the piles were examined. In the conclusion about their strength, it is said that the piles from the larch forest, on which the underwater part of the city is based, seemed to have turned to stone. The tree has become so hard that both the ax and the saw can hardly take it.

Inspection of the pine piles taken from the port facilities showed that over 30 years of operation they have reduced their strength properties by 40-70%.

Biological factors of destruction

Wood biodegradation mechanism

Since wood is a natural product of organic origin, it undergoes biological damage at certain temperatures and humidity.

Biological factors, or agents of biodegradation of wood, are living organisms that can have a destructive effect on wood, among them:

• mushrooms
• insects
• bacteria
• seaweed
• molluscs and crustaceans

Mushrooms are nature's most ruthless wood destroyers.

Fungal spores are found everywhere in our environment. Spores can infect wood even in the forest, when sawing, transporting unprotected wood, as well as when operating in buildings. During maturity, the fungus produces millions of spores per day, and although many of them die, it is also sufficiently carried by animals, insects and the wind, leading to infection of unprotected wood. Infection can also occur through the mycelium if the infected part comes into contact with healthy wood. As soon as fungal spores get into favorable conditions, they begin to develop rapidly and spoil the wood.

One of the most common situations is that building materials are harvested in winter (the "winter forest" is considered the healthiest), and its use begins only in summer. For storage, the wood was piled up and covered with polyethylene. Everything seems to be correct. But the greenhouse effect was not taken into account. And this effect is just a blessing for the mold. Heat and moisture are enough for the fungi to multiply and color the wood.

The development of fungal infections of wood is facilitated by warm (5-30 ° C) and humid conditions (W more than 22%) of the environment, the absence of air exchange.

Fungi that infect wood are very diverse - from mold that stains the wood superficially to wood-destroying fungi that penetrate into the thickness of the wood and destroy it almost completely.

A plexus of very thin mushroom filaments (hyphae) forms the fruiting body (mycelium, or mycelium). Spores mature in special carriers - conidia (such mushrooms are called wood-staining and moldy), or in fruit bodies - such mushrooms are called wood-destroying ones.

Fungi represent a large and distinctive group of unicellular and multicellular microorganisms. The total number of their species, described to date, is, according to various authors, from 10 to 250 thousand. They are widespread in nature in all regions of the world. Filamentous fungi of various genera are isolated from foci of damage to materials, but more often than others, representatives of two genera cause damage to materials: Aspergillus and Penicillium. Mushrooms have a mycelial vegetative body. It is a system of branched filaments - hyphae, the thickness of which ranges from 2 to 30 microns. Hyphae grow only in length, and their growth is practically unlimited. The growth rate ranges from 0.1 to 6mm / hour and depends on the rate of nutrient intake. The mycelium begins its development from spores that germinate at a certain temperature and humidity. First, the spore swells, absorbing moisture from the environment, then its shell breaks, and one or more growth tubes appear, which are the beginning of a new mycelium. At first, the development of hyphae is due to the reserve substances of the spore, and later - by the adsorption of nutrients from the material susceptible to biological damage.

Depending on the nature of growth, substrate and aerial mycelium are distinguished. The substrate mycelium is located on the surface of the material or penetrates it into the depths. In this case, the damage looks like a concentric formation pressed against the substrate. Aerial mycelium freely rises above the substrate, in contact with it only at certain points. Reproductive organs are usually formed on it. In this case, the damaged area resembles cotton wool. The growth pattern of the same fungus may vary depending on environmental conditions (composition of nutrients, humidity, etc.). Mushrooms reproduce either by part of the mycelium, which gives rise to a new organism, or by spores formed on special mycelium hyphae. Fungi form a very large number of spores.

Fungi that develop on wood (xylophiles, xylotrophs), practically all belong to three classes of higher fungi, which have divided into cells (septate) hyphae. These are Ascomycetes (Ascomycetes, marsupial mushrooms), Deuteromycetes or imperfect fungi (Deuteromycetes, Fungi imperfecti), and Basidiomycetes (Basidiomycetes) - the most powerful destroyers.

At the first stage, upon defeat, fungi appear on the wood, feeding on the juices of a living tree. Such as molds Penicillium, Aspergillus, living on the surface of wood. Then, in optimal conditions prepared by molds, wood-coloring fungi begin to multiply. The destruction of wood is completed by storage and wood-destroying mushrooms. They cause strong decay of wood, leading to the appearance of longitudinal and transverse cracks, and then wood mineralization.

In molds, the superficial part of the mycelium develops on the surface of the wood and forms a plaque on it in the form of an accumulation of colored spores, mycelium and sporulation organs. Under the mold, the wood usually does not change color, although it is penetrated with the hyphae of these fungi. The lack of paint is due to the fact that the hyphae in the wood are colorless and do not emit pigment. On wood, mold is usually greenish and white, but sometimes pink, yellow or dark. The optimum humidity for the development of molds is 60-100%, with a humidity of 40%, their growth slows down. Mold fungi develop in a temperature range of 24-30 ° C. At temperatures above 80 ° C and below -10 ° C, fungi that are in the vegetative stage of development die. The rate at which mold develops depends on the water absorption of the coating and the humidity in the air. Nutrients enter the cell in a dissolved form, therefore, for the normal development of fungi, the environment must contain a large percentage of water. Molds are the causative agents of oxidative fermentation. Organic acids such as gluconic, fumaric, tartaric, malic, oxalic, succinic and citric acids are formed as intermediate products of this biochemical process. These acids eat away organic materials, i.e. wood. Molding of materials is accompanied by a deterioration in the appearance of wood, which reduces the grade and cost of sawn timber. The main types of molds: Sporotrichum, Trichoderma, Penicillium, Mucor, Thamnidiu, Cladosporium.

Rice.
A) Colonies
B) Under the microscope
C) On wood

Wood-coloring fungi cause a specific bluish-gray color of sapwood, called "blue". According to global practice, the discount for wood affected by blue is from 20 to 50%. In Russia, it is often possible to meet a situation when blue-stained wood is sold at the price of firewood.

Depending on the type of mold fungus, the nature and conditions of infection and distribution of fungal hyphae in wood, surface color and deep color are distinguished.

Macroscopic signs of damage to wood by these fungi in the form of color usually appear as early as 2-3 days after infection. This is due to the fact that the young mycelium is colorless and does not start to release the typical pigment immediately. On the surface of the wood, aerial mycelium and sporulation organs can develop in the form of a fluffy or powdery colored plaque. Depending on the nature of infection and distribution in the wood of fungal hyphae, superficial and deep blue are distinguished. Surface staining penetrates into the wood by no more than 2 mm. It often looks like small spots with a diameter of 10-20 mm - round or oval. The slightly elongated shape is due to the faster growth of fungi along the fibers. The limited spread of fungi deep into the wood is associated with a delay in their growth as a result of drying out of the wood or the action of any other unfavorable factors. Less often - as a result of the peculiarities of the development of the mushrooms themselves.

Deep colors penetrate more than 2mm into the wood. Among them, there are solid, covering the entire sapwood (deep blue) and spotty, affecting individual areas of the sapwood.

The sublayer blue is very insidious, it forms in the inner layers of the wood, and is not visible on the surface. It usually occurs when fungi stop developing in the outer layers of the wood before color appears, but continue to develop inside the wood.

The depth of the coloration in case of sublayer blue depends on the type of fungus, the size of its characteristic zone of colorless young mycelium (zone of hidden blue), the width of which ranges from 5 to 12 mm.

Cushioning blue occurs when lumber is stacked on non-antiseptic strip or on damp and contaminated battens. These lesions are limited to the places where the sawn timber contacts the pads, and depending on the conditions and type of fungus, they can be deep and superficial. Fungi-causative agents of blue, caught from the air on the surface of freshly sawn wood in the form of spores, when penetrating into the depths, do not give color for two or more weeks (a period of colorless, hidden blue), and at a favorable air temperature and humidity of wood they paint it for the third fourth day.

Wood-coloring fungi develop optimally in the humidity range of 50-90%. In wood saturated with water, wood-coloring fungi are unable to develop due to the lack of oxygen. For the germination of this group of fungi, high humidity and aeration are required.

The main pathogens of blue stain on conifers are fungi from the Ascomycetes class: Ophistoma coerulea, O. piceae, O. pini, Endoconidiophora sp. and from the class of Deuteromycetes: Hormonema dematiodes, Trichosporium tingens, Claosporium herbarum, as well as mushrooms of the following groups: Stemphulium, Cladosporium, Alternaria, Sporodesmium, Phialophora, Aposhaeria, Discula, Burgoa, Pencilillium, Sortaria, Verticillium, Aspilces , Trichoderma, Chaetomium, Trichosporium, Pullularia. These fungi cause a "moderate rot" type of wood decay. Moreover, different mushrooms, causing destruction of an anatomically different nature, in varying degrees reduce the mechanical properties of wood. The depth of infestation by these fungi is 0.5-3mm. Special destructive hyphae are capable of infecting the walls of the parenchymal cells of the core rays and resin ducts, which leads to an increase in the rate of water and moisture absorption of wood. As a result, its resistance to impact bending decreases.

A) Colonies
B) Under the microscope
C) On wood

Wood-coloring mushrooms are capable of changing the properties of wood to varying degrees.

Mold and blue fungi spoil the appearance, reduce the grade of wood, increase water absorption and produce millions of spores that can cause allergic diseases in humans.

After a one-month exposure to blue fungi on wood, the rate of water absorption of pine can increase by 1.5 times. With the further development of fungi, many of them are capable of destroying the walls of the heart-shaped rays and secondary layers of the cell walls in a manner close to moderate rot.

Wood-coloring mushrooms are just the beginning of a process that can lead to a total defeat of wood by more terrible enemies - wood-destroying fungi, which are a real danger to wooden structures.

Shaving off the blue from the surface of lumber may not provide complete removal of hidden blue. The most effective measure to prevent wood from staining with blue during air drying is antiseptic treatment.

Wood-destroying mushrooms

Some classes of fungi can destroy the cell walls of wood and significantly change its physical and mechanical properties. This process is called wood decay, and the fungi that cause it are wood-destroying. Rotting is the main cause of wood destruction.

There are many wood-destroying fungi. They differ in shape, structure and color of mycelium, cords, fruiting bodies and spores, as well as in the speed and strength of wood destruction.

The most powerful destroyers are fungi belonging to the class of Basidiomycetes. Xylotrophic basidiomycetes are fungi that form large fruiting bodies (carpophores), the spore-forming layer of which is called the hymenophore. On the surface of the wood, in addition to aerial mycelium, they form other vegetative mycelial structures.

Wood-destroying fungi are able to moisturize wood in the process of development due to the water formed during the decomposition of cellulose. The causative agents of wood biodamage are mainly related to the following groups of fungi: Coniophora, Tyromyces, Zentinus, Serpula, Gloeophyllum, Trametes, Pleurotus, Schizophyllum.

A) So they spoil the wood
B) Colonies of Serpula lacrimans

The nature of decay depends on what enzymes the fungus acts on the wood, what components of the cell walls and in what sequence it destroys.

At the beginning of the activity of wood-destroying fungi, the appearance of the wood does not change, and the presence of fungal filaments in it can be detected only under a microscope, in a thin section. Subsequently, the wood changes its natural color, becomes yellow or reddish, and then brown and brown. The density and strength of wood gradually decreases, it becomes light, soft, and loses its viscosity.

Rot of this type is called destructive. It is characteristic mainly of mushrooms that destroy the wooden parts of buildings, the so-called house mushrooms.

House mushrooms are a group of wood-destroying microorganisms that have adapted to environmental conditions in buildings and structures. During their development, these fungi form threads visible to the eye on the surface of the wood, which are called mycelium. The mycelium, densifying, turns into films, cords and fruiting bodies, on which spores are formed. Bright representatives a class of wood-destroying mushrooms is Coriolus sinuosus - white house mushroom.

Some fungi that infect growing trees cause a different type of rot - corrosive, in which first small light spots and pits appear, and then the wood is split into separate fibers. This group of fungi primarily uses wood lignin, leaving the cellulose intact, with white spots and efflorescence visible on the cut surface. Corrosive rot also includes core rot: variegated, pitted, sieve.

With the development of moderate (Softrot) rot, the surface layers of the wood lose their structure and turn into a soft dark mud-like mass. After drying the wood in the affected layer, there is a strong drying out and the appearance of small longitudinal and transverse cracks. The causative agents of moderate rot are complexes of some imperfect fungi, bacteria, and algae.

By the type of rot formed, the type of wood decay can be characterized as follows:

White rot destroys everything structural components wood, resulting in a characteristic fibrous and pale appearance. This is the main type of putrefactive fungi, leading to decay of deciduous trees that do not have contact with the ground.

Brown rot“Splits” the cellulose, which causes the wood to split. The area of ​​the tree affected by such rot turns brown. The tree darkens, cracks and crumbles. The fungus grows catastrophically quickly, especially in soft wood buildings; pine and oak wood is less damaged by fungus. The defeat of wooden structures by such mushrooms causes significant damage to the supporting structures, not to mention the aesthetic characteristics of the house.

Soft rot... Rotting here mainly affects wood in contact with soil and found in the marine environment. It affects wood with a high moisture content most of all.

Other biodeterioration agents

Woodworm insects

The wood is damaged by various insects - beetles (longhorn beetles, golden beetles, bark beetles, weevils, woodcutters, grinders), horn-tails, termites, ants and others. Some of them make moves only in the bark, while many go deep into the wood.

Insect larvae make tunnels and holes in the wood - wormholes. Being in wood, woodworms are able to gnaw through passages up to 40 meters in length.

Insect damage is so significant that parts of the tree lose their strength. Often, with a small number of external holes, the wood is completely destroyed inside.

A separate problem associated with the international timber trade is the import of tropical varieties already infested with insects.

Rice.

Of the pests, the most dangerous is a furniture grinder. He makes numerous passages in wood with a diameter of up to 2 millimeters, destroying furniture, as well as structural elements and parts of buildings and structures, turning the wood into a dusty mass under the preserved thin outer layer.

Bacteria

Bacteria destroy wood to a limited extent, they, multiplying by cell division, cannot move in wood, except for the one that is under water. Bacteria tend to colonize wood cells using proteins as food sources. The bacteria are capable of breaking down polysaccharides and lignin. Bacterial exposure is limited to sapwood, and heartwood components are resistant to this.

Seaweed

Algae usually appear as green growths, especially on the north side of wooden facades. Their growth is the result of too high surface moisture content.

Algae themselves do not cause rotting, but are indicative of an increased moisture content in the wood, which is associated with the risk of fungal damage.

Crustaceans and molluscs

Crustaceans and molluscs attack wood in seawater. The adults and their larvae destroy the wood through the mechanical drilling process and eat it. The ship's worm moves first go perpendicular to the surface to a depth of 10-30 mm, then turn and go up and down the annual layers, while the individual passages never intersect or merge. Damage to port facilities and ships by marine woodworm molluscs and crustaceans is attributed to rotten wormhole.

Climatic factors of destruction

When used in buildings, wood is constantly influenced by natural factors, which, together with biodegradation agents, lead to a deterioration in the appearance, aging and destruction of wood.

Wind, dust, precipitation, temperature changes lead to shrinkage, swelling, cracking, warping, moisture accumulation, and an increase in the risk of biological damage to wood.

Solar radiation leads to a chemical change in cellulose, the destruction of lignin, the wood acquires a grayish tint and hairiness.

The greatest harm to wood is caused by changes in moisture and solar radiation.

With constantly changing weather conditions, the moisture content of the wood will change, leading to shrinkage, or swelling. Over time, wood cracks and warps, which in turn increases the risk of rainwater entering the wood. Since water in a liquid state can only escape from wood through (slow) evaporation, the risk of moisture accumulation increases over time. If the moisture content exceeds 20%, the risk of fungal attack increases. The longer the period during which the moisture level is above 20%, the higher the risk of developing fungi. Many types of wood contain colored water-soluble compounds that are leached out by water, resulting in discoloration of the wood surface.

Sunshine and warmth

Sunlight is heterogeneous in nature, it consists of studies of different wavelengths, each of which has its own peculiarity of impact on wood.

IR component spectrum, with a wavelength of more than 720nm, when interacting with wood, heats it. Since wood is a good insulating material, only the outer surface is heated. This means that on the surface, due to shrinkage caused by elevated temperatures, cracks may form.

Elevated temperatures also cause knotting and resin build-up in softwood, which can lead to problems in re-coating the surface.

Visible light(wavelength 380-720nm) has no harmful effect on wood.

UV component spectrum with a wavelength of less than 380nm, causes the destruction of wood at the molecular level - the destruction of lignin. As a result, the wood darkens quickly and the fibers flake off and rise.

The wood becomes gray and fluffy. To preserve the original color of wood, it must be protected with film-forming protective and decorative coatings containing a UV filter. These coatings include the SENEZH AQUADECOR tinting antiseptic.

Wood as a building material:

• Part IV: Factors of Wood Destruction

Pine wood is sound, shiny, resinous. The core is brownish-red, formed at the age of 30-35. In a growing tree, the core plays a mainly mechanical role, giving the trunk the necessary stability.

Therefore, a tree affected by heart rot looks healthy outwardly, but loses its marketability. The sapwood is wide, yellowish or reddish white. The annual layers are clear. Resin passages, in the form of thin channels, numerous, scattered singly or in pairs. Occupy by volume 0.1-0.7% of the volume of wood.

The core beams are 0.5 mm high, denser than the surrounding wood. There are more than 3 thousand of them per 1 cm 2 of tangential cut. They serve for the transfer and storage of nutrients.

Conductive and mechanical functions in pine are performed by tracheids (90-95% of the total wood volume). The width of the tracheids is 0.04 mm, and the length is 4-5 mm. Trees of the highest developmental classes (plus) form larger tracheids than trees that are stunted in growth.

According to the degree of density, pine wood is divided into kondovy (ore) and honey. The first is yellowish-red, finely layered and dense. The second is white, large-layered, with a thick layer of sapwood, low resinousness and friability. Kondovaya is formed in trees growing in mountains or high forest areas, myandovaya - in trees growing in low, sandy locations or on loams and chernozem-like sandy loams. In appearance, Siberian cedar wood is similar to mint wood. It is slightly resinous. Although Siberian cedar in physical and mechanical properties occupies an intermediate position between Siberian spruce and Siberian fir, a feature of cedar wood is its light and smooth carving in different directions. For its beautiful texture, cedar wood is used in joinery and furniture production.

The volume of pine bark, which protects the tree from external conditions, is 10-17% of the volume of the trunk in the bark. The plant origin of wood determines the great variability of its properties. The volumetric weight of pine wood depends on the growing conditions. So, in the Arkhangelsk region in a mossy forest, it is 0.50-0.55 g / cm 3; in the Moscow region - 0.59-0.62, and: in Yakutia - 0.41 g / cm 3.

Pine wood is highly durable. The ultimate strength in compression along the fibers is 439 g / cm 2, with static bending - 793 kg / cm 2, hardness - 200 kg / cm 2 (the center of the European part of the USSR).

The wood of the northern pine is especially famous worldwide. Its annual layers are characterized by a high content of late thick-walled tracheids in all types of forest, with the exception of the swamp forest. The physical and mechanical properties of the northern pine are much higher than the pine of the center of the European part of the USSR. Twenty-four-hour vegetation (at the polar bottom) and the beneficial influence of the Gulf Stream contribute to the formation of high-grade pine wood in the north.

It is also interesting to note the great preservation of pine wood. So, during the excavations in Armenia of the Urartian fortress of Teishebaini, a log of Caucasian pine lay for 2,700 years and had the following indicators: volumetric weight - 0.38 g / cm 3, ultimate strength in compression along the fibers - 200 kgf / cm 2, with static bending - 223 kgf / cm 2, end hardness - 262 kgf / cm 2. This preservation of wood was facilitated by a layer of clay, which protected the log from moisture, created a lack of oxygen and protected the wood from biological destructors. Pine logs of ancient buildings in Brest (XIII century) had an average density in an absolutely dry state of 0.35-0.37 g / cm 3.

Currently, for the long-term preservation of pine wood, deep impregnation with a low molecular weight water-soluble synthetic resin is used, followed by hardening. For modification, or plasticization, pine wood is impregnated (at a moisture content of 9-10%) with gaseous ammonia (3%), then piezothermal treatment (at 170 °) and compaction are carried out. After processing, the tensile strength increases by almost 2 times. When modifying pine wood, cellulose and lignin are especially affected. Pine wood plasticized with ammonia can be used for the preparation of machine parts, furniture, musical instruments, lining of mines, wiring accessories, solid sawdust boards, parquet, etc. based on styrene - after modification the wood acquires a light golden hue and shine. The swelling dynamics slows down several times.

The growth of the annual layer of Scots pine wood is accompanied by a change in the biological composition of the tissues of young shoots. At the beginning of the active development of cambium, protein contains up to 22.7% of the absolute dry weight of tissues. At the end of development, the protein content is reduced to a minimum. There is also a decrease in starch from 15.5% to 5.2% and amylase. But there is an accumulation of monoses, sugars (up to 14.7%), which are then quickly spent on the construction of secondary tissues.

In the xylem sap of suppressed pines, an increased concentration of monoses, oligosaccharides, and amino acids was noted in comparison with normally developed pines. In the tissues of such pines, the processes of biosynthesis of polymeric compounds necessary for the construction of new cellular structures are also weakened.

As a result of air pollution with sulfur dioxide, pine tree rings are characterized by weak growth and deformation. First of all, the parenchymal cells of the cortex die off. Stronger smoke leads to deformation and destruction of bast, cambium, pith rays and resin passages.

Pine wood is used for the production of plywood, as a raw material in the pulp and paper industry (technological chips), it occupies one of the main places in the country's timber exports (exported in the form of lumber, sleepers, props, etc.). V early period aircraft - and glider building pine was one of the main materials.

It is interesting to note that the Forestry Department of the National University of Australia in Canberra uses beech wood from England, eucalyptus and acacia from Australia, American walnut from America, mahogany from Canada, alpine elm from America, wood from New Zealand, for decoration of premises for decorative purposes. and the second floor auditorium is clad in California pine.

The soft, pinkish wood of Siberian cedar, beautiful in texture, goes on the shell of pencils, musical instruments, furniture, on battery veneer. Milk does not sour for a long time in a cedar container (dishes), moths do not start from a cedar in a cupboard, ticks and mosquitoes are frightened off by the essential smells of a cedar, bees feel best in a cedar hive.

Interestingly, with age, the content of pinene in wood increases and the amount of one of the monoterpenes, karene, the most toxic component of the tree's defense system, decreases.

Pine firewood is used to burn coal. From 10 m 3 of firewood, 670 kg of coal are heaped, and 875 kg are obtained with the stove method.

In the production of green tea Kok-Cha (India), the furnaces for heating and drying the leaves are fired only with pine branches.

The problems of the structure of the physical and mechanical properties of wood and its biostability have been studied by many researchers: D. A. Belenkov, I. A. Alekseev, S. F. Negrutskiy, I. A. Petrenko, R. S. Stepanov and others. Swedish wood scientists Heningson and Messon.