As in the old days, young spruce undergrowth was called. Assessment of the vital condition of coniferous undergrowth

Spruce forest vegetation

TEENAGE

Municipal educational institution

Oktyabrskaya secondary school

Manturovo municipal district

Kostroma region

Spruce forest and its undergrowth

Completed:

Borodinsky Ilya Pavlovich

8th grade student

Municipal educational institution Oktyabrskaya secondary school

Supervisor:

Smirnova Tatyana Valerievna

1. Introduction. 3

2. Research methodology. 4 3.Results of the study.

3.1. Features of the spruce forest. 5

3.2. Species composition of spruce forest. 7

3.3. Young spruce forest. 8

3.4. The influence of mature trees on the growth of spruce seedlings and spruce undergrowth. 8

3.5. The influence of mature trees on the formation of young trees. 9

4. Conclusions. eleven

5. Conclusion and prospects 12 6. List of references. 13 7. Applications. 14

1. Introduction

Most of our area is occupied by spruce forests. The spruce forest is a completely special, unique plant community. This forest is gloomy, shady, damp. If you enter a spruce forest from a field or meadow on a hot summer day, you will immediately find yourself in deep shade and feel cool and damp. The whole situation here is sharply different from what is typical of an open place. Spruce greatly changes the environment and creates specific conditions under its canopy.

The composition of plants in the lower layers of the forest is largely determined by the properties of the soil. In those parts of the spruce forest where the soil is poorer in nutrients and more moist, we usually find dense thickets of blueberries on the moss carpet. This type of forest, found near the village of Oktyabrsky, is called a spruce-blueberry forest.

Goal of the work:

study the spruce forest and the undergrowth of the spruce forest.

Tasks:

Find out the features of the spruce forest;

Study the species composition of the spruce forest;

Study the undergrowth of the spruce forest;

Conduct research and identify the influence of mature trees on the growth of spruce seedlings and spruce undergrowth;

Identify the influence of mature trees on the formation of undergrowth.

2. Research methodology

We conducted research work in the summer of 2011.

For our research we used the following equipment: pegs, measuring fork, tape measure.

When performing this work, we used observation and comparison methods. Using the observation method, the species composition of the spruce forest, the external features of the undergrowth and the spruce forest seedlings were studied. The tables were compiled based on the comparison method. This method made it possible to consider and compare the number of sprout sprouts and regrowth, and also helped to determine the final results in this work.

As a result of the analysis of literary sources on biology and ecology, we became acquainted in detail with the vegetation of the spruce forest, soils, growing conditions,,,

3.Research results

3.1. Features of the spruce forest

The spruce forest is a completely special, unique plant community (Appendix I photo1). Spruce creates very strong shading, and only fairly shade-tolerant plants can exist under its canopy. There are usually few shrubs in a spruce forest. The plants that we see under the canopy of the spruce forest are quite shade-tolerant; they not only grow normally in deep shade, but even bloom and bear fruit. All these plants also tolerate the relative poverty of the soil in nutrients and its high acidity (such properties are characteristic of the soil of a spruce forest). At the same time, many spruce forest plants are demanding of soil moisture.

There is almost never any strong air movement under the canopy of the spruce forest. And in the spruce forest you will hardly find plants whose seeds would have any “parachutes” or other devices for dispersal by wind. But there are many plants whose seeds are extremely small, look like dust and are spread even by very weak air currents.

Among the plants found in spruce forests, there are many that have white flowers.

This coloring of flowers is not accidental. This is an adaptation to the poor lighting under the canopy of a spruce forest. White flowers are more visible in the twilight than any other, and are easiest for pollinating insects to find.

Almost all herbaceous plants in the spruce forest are perennial. Every spring they continue their life, but do not start it all over again, from a seed, like annual grasses. They occupy their specific place in the forest for many years. Most plants in the spruce forest have more or less long creeping rhizomes or above-ground shoots that can quickly grow laterally and take over a new area. All these are adaptations to the specific environment under the canopy of the spruce forest. The emergence of new plants from seeds here is fraught with great difficulties: the germination of fallen seeds is hampered by a thick layer of dead needles on the soil and a moss cover. Reproduction by seeds under these conditions is very unreliable. The inhabitants of the spruce forest maintain their existence mainly through vegetative reproduction. Shoots of any plants can appear from seeds only in special conditions - where the layer is removed

fallen pine needles along with the moss cover and the soil was exposed. It is precisely these conditions that are necessary for the mass emergence of sprouts, even of spruce itself.

The litter in the spruce forest has a highly acidic pH and is decomposed almost exclusively by microscopic fungi. The fungal population is very abundant not only in the litter, but also in the upper layers of the soil. It is not surprising, therefore, that many plants of the spruce forest have mycorrhizae; their roots are braided with a thick cover of the finest fungal threads - hyphae. Mycorrhiza plays important role in the life of forest plants, helps them absorb hard-to-reach materials from the soil nutrients. Some herbs of the spruce forest are so closely associated in their life with the mycorrhizal fungus that even their seeds cannot germinate without the participation of the fungus.

Another one characteristic feature spruce forest plants - the fact that many of them remain green for the winter and retain living foliage in the cold season. In the spring, as soon as the snow melts, you can always see their old, overwintered green leaves on the soil. It gets a little warmer - and the process of photosynthesis immediately begins in the leaves and organic substances are produced. Relatively few grasses of the spruce forest completely lose their above-ground parts in the fall and overwinter only in the form of underground organs.

Shrubs play an important role in the living ground cover of a spruce forest. All these plants do not differ from shrubs in their structural features, but are only significantly smaller in size.

The mosses that we see on the soil in the spruce forest are very shade-tolerant plants. They can exist in fairly low light. They also tolerate the mechanical impact of dry needles falling from trees. There is no moss cover only in very dense young spruce stands, where almost no light reaches the soil. The appearance of the spruce forest changes little throughout the year. Spruce remains green all the time, and so do many forest herbs. Unaltered green color also retains the moss cover. Only in spring and early summer do we see some diversity, when some of the grasses along the canopy of the spruce forest begin to bloom.

3. 2. Species composition of the spruce forest

In a spruce forest, the main species is common spruce or Norway spruce (Appendix I photo 2). The root system is taproot for the first 10-15 years, then superficial (the main root dies). The tree is slightly wind resistant. The crown is cone-shaped or pyramidal. The branches are whorled, horizontally spread or drooping. In the first 3-4 years it does not produce lateral shoots. The bark is gray and peels off in thin sheets. The leaves are needle-shaped (needles), green, short, tetrahedral, less often flat, hard and sharp, with 2 keels on the upper and lower sides. Arranged spirally, singly, sitting on leaf pads. They remain on shoots for several (6 or more) years. Up to one-seventh of the needles fall annually. After severe consumption of needles by some insects, for example, the nun butterfly, brush shoots appear - with very short and stiff needles, reminiscent of appearance brushes

Gymnosperm plants. The cones are oblong-cylindrical, pointed, do not crumble, and fall off whole when the seeds ripen in the first year of fertilization. Mature cones are hanging, dry, leathery or woody, up to 15 cm long, 3-4 cm in diameter. The cones consist of an axis on which numerous covering scales are located, and in their axils there are seed scales, on the upper surface of which 2 ovules usually develop , equipped with a so-called false wing.

The seeds ripen in October and are dispersed by the wind. They do not lose germination for 8-10 years.

The beginning of fruiting is from 10 to 60 years (depending on growing conditions).

Lives on average up to 250-300 years (sometimes up to 600)

Pure spruce forests are very dense, dense, and dark. Common birch is found near spruce trees, but very rarely. There is almost no undergrowth in the spruce forests, only sporadic common juniper and mountain ash are found. The herbaceous-shrub layer is well developed. Blueberries form a continuous well-developed layer. Sometimes mixed with it in significant quantities are common lingonberry, two-leaf lingonberry, common sorrel, horsetail, and male shield. The moss cover of blueberry spruce forests is sparse and consists of patches of sphagnum moss and cuckoo flax. After felling, in the places of former blueberry spruce forests, reed grass, pike or willowherb clearings appear, then birch, aspen and blueberry-broadgrass pine forests.

Having studied the species composition of the spruce forest, the data was entered into a description form (Appendix II)
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3.3. Spruce forest undergrowth

Undergrowth - a young generation consisting of woody plants of natural origin growing under the forest canopy, capable of forming the main canopy of a tree stand, not reaching the height of the main tree stand

Undergrowth under the dense canopy of a mature forest has a difficult existence. Seedlings that find themselves on the edge, in a clearing, in areas where enough light penetrates into the gaps in the crowns formed after the old tree fell out, grow well. In such plants, the branches start from the very ground, they are densely covered with foliage or needles of a bright green color, their apex is well developed.

Under the canopy of the spruce forest there are many young spruce trees that did not find themselves in such favorable conditions, and they are forced to be content with what they got. And they got very little. Typically, the undergrowth grows in groups and is concentrated in conditions favorable for seed germination and the initial period of seedling growth. But as they grow, rivalry begins within the group of undergrowth; in addition, the trees are shaded by the upper canopy of the mature forest, and they have to be content with the remnants of the light that penetrated through the crowns of the trees of the older generation. The roots of the undergrowth develop in soil already occupied by the root system of the old forest, and they have to limit themselves to less food and moisture. You can often see one-meter-long fir trees in such undergrowth in a dense spruce forest, which are 30-50 years old.

In depressed undergrowth, the apical shoot is almost invisible; the branches are located only in the upper part of the stem and are located horizontally, so more light reaches them.

In a natural forest, over the years, old trees become decrepit, gradually different time fall out and gaps between the trees increase. More light, more moisture in the forest - less competition between the younger generation and the root system of the mother forest. The juvenile recovers, adapts to new conditions and accelerates growth, wedging its apex into the upper canopy. Even after 80-100 years of oppression, spruce can recover and become part of the upper canopy.

The undergrowth can be of seed or vegetative origin. Young shoots of seed origin early stage called self-seeding (for coniferous and deciduous trees with heavy seeds) or bloom (for birch, aspen and other deciduous trees with light seeds). Plants up to 1 year old are considered to be seedlings. One of the important means of forest restoration is the preservation of undergrowth from damage during logging. 3.4. The influence of mature trees on the growth of spruce seedlings and spruce undergrowth

We chose an area of mature spruce forest (away from roads) with well-defined dead spots under the crowns of mature trees and with a moss carpet between them. We found a spruce tree, under the crown of which there is big number young seedlings (Appendix III photo1), and 5 areas measuring 100 cm 2 (10 * 10 cm 2) were laid here. Another series of platforms were placed between the treetops on a thick moss carpet. We counted the number of spruce seedlings on each plot, and then calculated the average data per plot. The results were entered into the table (Appendix III table 1)

In the same areas (i.e. under the crowns of spruce trees and between them) lay platforms bigger size– 1 m2 and calculated the amount of undergrowth present on them (Appendix IV photo1), without shoots. The data was entered into the table (Appendix IV table 1)

We compared the results and made conclusion:

spruce seedlings appear in greater numbers per unit area directly under the crowns of mature trees, since a thick layer of moss prevents their appearance between the crowns; The seedlings die before their roots reach the soil. Vice versa, greatest number grown Christmas trees are located between the tree crowns. This discrepancy in the places where trees of different ages are abundantly found is due to the influence of mature trees. Under the crowns, due to strong competition (primarily for light), all seedlings quickly die. In the intercrown areas of the forest, the influence of mature trees is weakened, and here the majority, even of the total small number, of the emerging fir trees are preserved.

3.5. The influence of mature trees on the formation of young trees.

During the research, the state of spruce undergrowth in the forest and at the forest edge was described in order to identify the influence of adult plants on the formation of undergrowth. The undergrowth is of medium height, medium density, uneven, viable.

We chose young fir trees of approximately the same height - 1-1.5 m, growing in the shade of the forest, on its edge or in a clearing; studied them external structure and the data was entered into a table (Appendix V Table 1).

Done conclusion:

On the edges and clearings the condition of the undergrowth spruce forest is good. Here the crowns of the Christmas trees are cone-shaped, with densely spaced, well-covered branches. Under the forest canopy, the crowns of the fir trees are umbrella-shaped, with sparse and weakly covered branches that are strongly elongated to the sides. Moreover, in the bright areas of the forest, undergrowth grows densely, and in the shade, fir trees are found sporadically and rarely. These differences in condition and abundance
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teenagers in different areas forests indicate the unfavorable influence of mature trees, which occurs through changes in living conditions: shading, etc.

From a comparison of the results, it is clear that the influence of mature spruce trees also affects the undergrowth growing between their crowns, but here it is weakened compared to the sub-crown areas; This influence has even less effect on young people who grow up at the edge of the forest.

conclusions

As a result of the work done, we learned much more about the spruce forest, its species composition, and also studied the influence of mature trees on the growth of spruce seedlings and undergrowth, as well as on the formation of undergrowth.

After the research we came to the conclusion

There is no great species diversity in spruce forests, and only shade-tolerant plants grow.
Spruce seedlings appear in greater numbers per unit area directly under the crowns of mature trees, since a thick layer of moss prevents their appearance between the crowns; The seedlings die before their roots reach the soil. On the contrary, the largest number of grown Christmas trees are located between the tree crowns. This discrepancy in the places where trees of different ages are abundantly found is due to the influence of mature trees. Under the crowns, due to strong competition (primarily for light), all seedlings quickly die. In the intercrown areas of the forest, the influence of mature trees is weakened, and here the majority, even of the total small number, of the emerging fir trees are preserved.
At the edges and clearings the condition of the undergrowth spruce forest is good. Here the crowns of the Christmas trees are cone-shaped, with densely spaced, well-covered branches. Under the forest canopy, the crowns of the fir trees are umbrella-shaped, with sparse and weakly covered branches that are strongly elongated to the sides. Moreover, in the bright areas of the forest, undergrowth grows densely, and in the shade, fir trees are found sporadically and rarely. These differences in the condition and abundance of undergrowth in different parts of the forest indicate the unfavorable influence of mature trees, which occurs through changes in habitat conditions: shading, etc.

Conclusion

In our area there are coniferous forests and the predominant species in these forests is spruce. Every year the number of forest plantations is reduced as a result of logging and unauthorized logging.

Undergrowth is a young generation capable of forming the main forest stand. It is the main replacement of a dead or cut down forest, so we must study and protect it.

In the future, I want to continue my work on studying the spruce forest stand, as well as other tree crops.

List of used literature

1. Biological encyclopedic Dictionary. Ch. ed. M. S. Gilyarov and others - 2nd edition corrected. - M.: Sov. Encyclopedia, 1989

2. Lerner G.I. Dictionary-reference book for schoolchildren, applicants and teachers. – M.: “5 for knowledge”, 2006.

3. Litvinova L.S. Moral and environmental education of schoolchildren. - M.: “5 for knowledge”, 2005.

4. Rozanov L.L. Dictionary-reference book. - M.: NTSENAS, 2002.

Appendix I

Photo 1. Spruce forest

Photo 2. Norway spruce

Appendix ΙI

Description July 15, 2010

Name of associations: spruce forest - blueberry

General character of the relief: flat

Soil (name): sod-podzolic loamy

Humidification conditions: not uniform

Dead litter (composition, thickness, degree of coverage, nature of distribution): last year's needles, continuous covering, evenly distributed, 2 cm

Species composition of tree species

Species composition of undergrowth

Species composition of the shrub layer

Species composition of the herbaceous-shrub layer

№ p/p	View	Latin name
1.	Blueberry	Vaccinium myrtillus
2.	May lily of the valley	Convallaria majalis
3.	Maynik two-leaf	Mojanthenum bifolium
4.	Common lingonberry	Vaccinium vitisidaea
5.	Common oxalis	Oxalis acetosella
6.	Male shieldweed	Dryopteris filix-mas

Appendix II

Photo 1. Spruce shoots

Table 1. Number of spruce shoots

Appendix ΙV

Photo 1. Young spruce

Table 1. Amount of spruce undergrowth

Appendix V

Table 1. Condition of spruce undergrowth in different conditions

Undergrowth can be used for reforestation of cleared areas in many cases with very great effect. The use of spruce, cedar and fir undergrowth is especially important, since the subsequent regeneration of forest stands of these species is associated with great difficulties due to the very slow growth of undergrowth in the first years of its life. [...]

In many cases, spruce undergrowth recovers from cutting much more slowly than pine (Fig. 36). In the first 2-3 years, growth decreases or increases slightly. In subsequent years, the growth increases noticeably, especially in green moss forests (better in pine forests, somewhat worse in spruce forests).[...]

Pine undergrowth is a source of seeding of a narrower geographical and forest typological range compared to spruce. Nevertheless, it is also an important source of seeds for some areas and types of forest. In the northern taiga regions, pine trees begin to bear fruit early. In concentrated clearings of the Kola Peninsula, fruit-bearing undergrowth and even pine seedlings are found. Under the same conditions, in 25-35 year old pine trees on lichen and shrub-lichen clearings, up to 50% of trees or more bear fruit in productive years.[...]

Thus, undergrowth for concentrated cuttings not only itself is the basis of the future forest stand as a preliminary regeneration, but under certain conditions it serves as one of the important sources of seeding of these cuttings.[...]

The occurrence of undergrowth’ was chosen as one of the most important criteria for silvicultural and environmental requirements for the operation of logging machines during clear-cutting. Occurrence is a reliable indicator for assessing natural forest regeneration (Martynov, 1992; Tikhonov, 1979), allowing one to predict the composition and productivity of future forest stands. The occurrence rate can also be successfully used to predict subsequent forest regeneration based on the nature of forest growth conditions in fresh felled areas and the possible formation of one or another type of clearing or its fragments (parcels). The value of this indicator depends on forest conditions, biology and ecology of tree species.[...]

The use of teenagers has great importance for the renewal of oak, beech, hornbeam, linden forests. For satisfactory and good renewal, the old undergrowth of these species, which takes on a bushy creeping form, should be planted on a stump, i.e., cut down leaving a small stump, on which shoots then emerge from dormant buds (“sit down”), characterized by more slender growth than felled old undergrowth. Planting on a stump is also quite advisable for old undergrowth of elm, maple, chestnut and other species.[...]

For example, the amount of spruce undergrowth under the mother canopy per unit area naturally changes within the range of this species: it decreases to the north and south of the areas optimal for spruce growth. The southern border of these regions extends further to the south in the western, more humid part of the European territory of the USSR, and shifts somewhat to the north in the eastern, more continental (meaning flat areas). In the sparse and northern subzones of the taiga, the amount of spruce undergrowth per unit area is less than in the southern subzones, but at the same time, spruce grows here in a wide typological range; it even enters lichen forest types. It is necessary to take into account the comparative potential productivity of undergrowth of different tree species growing in the same area in order to place the main emphasis on the species that, under given physical and geographical conditions, is capable of forming the most highly productive forest stands. Thus, in the mentioned forests of lichen types, as well as in northern lingonberries, the productivity of spruce stands significantly lags behind pine ones. A unique feature of spruce regeneration in a number of areas of the European taiga is also its ability to appear as a pioneer in burnt areas and clear-cuts under certain soil and microclimatic conditions; this phenomenon was noted and described by the author in the late twenties and early thirties.[...]

Thus, the preservation of undergrowth is an important type of regulated natural regeneration. At the same time, it cannot be considered as the only way of natural regeneration during clear-cutting. So, for example, it is not advisable to rely on spruce undergrowth growing under the pine canopy on poor soils, where the productivity of the pine tree stand is much higher than that of spruce.[...]

The number of cones and seeds in young spruce and pine trees is less than in most adult trees. However, this is compensated by a large number of undergrowth plants and a possible improvement in seed quality. The most valuable is the undergrowth that grows before felling in windows and generally under the sparse forest canopy, since its fruiting may occur earlier during clearing. Such undergrowth sometimes bears fruit even before felling.[...]

Due to the fact that the preserved spruce undergrowth (20 years old at the time of felling) will subsequently occupy the first tier in the canopy of the emerging young growth, the need for thinning practically disappears. According to A. S. Tikhonov, spruce, growing from 15-20-year-old undergrowth, at the age of 70 years has the same height as birch and aspen. Thinning is necessary only in places with a predominance of small undergrowth preserved (during logging) and spruce undergrowth that is subsequently renewed. Within 10 years, the type of felling under consideration is transformed into the initial stage of the forest type - mixed-grass spruce forest (hereinafter - fresh blueberry).[...]

The growth of undergrowth in peaty sphagnum pine forests changes relatively little, which is associated with small changes in the light regime after felling and with unfavorable soil conditions.[...]

An external sign of the viability of a young tree can be its growth in height. With an average annual growth rate of 5 aa or more over the past 5 years, spruce and fir regrowth 0.5-1.5 m high can be considered quite viable, able to withstand sudden lightening of its upper canopy by clear cutting. [...]

The quality of forest stands formed from the undergrowth of preliminary generations is closely related to the nature of its damage during logging. Places of mechanical damage to spruce undergrowth are often affected by rot, which leads to a decrease in the quality of the wood. Spruce wood is affected by rot when the width of the wounds around the circumference of the undergrowth trunk is 3 cm or more. These wounds do not heal for a very long time, sometimes during the entire life of the trees. Smaller wounds heal within 15 to 20 years. Rot, formed as a result of wounds of the first kind, covers about 3 m of the butt part of the trunk over 60 - 70 years.[...]

It is much more difficult to preserve undergrowth in mountain forests than in lowland forests. A lot of undergrowth there is destroyed during unsystematic ground skidding by self-raising. Ground skidding with winches and tractors also causes more damage to undergrowth than in lowland forests. The steeper the slopes, the more undergrowth is damaged.[...]

In the forests of the taiga zone there is often a large amount of undergrowth, which is due to the high age and therefore the relatively low density of tree stands. The appearance of undergrowth under the canopy was also facilitated by ground-level runaway fires, which caused thinning of tree stands and damage to the ground cover (I.S. Melekhov, A.A. Molchanov, etc.).[...]

Sometimes, after felling, frail, although viable, spruce undergrowth remains, characterized by slow growth. Such undergrowth can only form a tree stand of low productivity. The reason for this is not only the suppression of undergrowth under the canopy and the reaction to lightening, but also soil conditions. It is advisable to replace such undergrowth by first preparing the soil by fire or some other method for subsequent artificial regeneration, for example, of pine, if this turns out to be cost-effective and leads to the formation of forest stands of higher productivity.[...]

Let's take, for example, two areas: in one there is evenly distributed coniferous undergrowth, in the other there is no undergrowth. In the first case, you can leave several insurance seeds per 1 hectare, in the other - more to ensure complete seeding of the entire plot.[...]

The study showed that the intensity of respiration of the conducting roots of spruce undergrowth, both in terms of the mass of CO2 released and the amount of absorbed O2, is higher in the clearing than under the forest canopy (Table 1). During the study period, respiration energy is subject to quite significant fluctuations, and from the second half of July there is a noticeable rise in the respiration curve associated with changes in both temperature environment, and soil moisture (Table 2). However, the increase in respiration intensity does not correspond to the temperature coefficient [...]

In economic practice, it is necessary to take into account and study not only the existing undergrowth under the forest canopy, but also... deforestation, burning, etc., but also the conditions for its appearance and development. An integral part of the issues of accounting and research of forest regeneration is the scientific and practical study of forest fruiting, as a necessary condition for seed-based reforestation, natural and artificial.[...]

When visiting the Buzuluksky forest, another thing that catches your eye is the presence of viable pine undergrowth under the sparse forest canopy, usually in windows. This characteristic phenomenon prompted G.F. Morozov and other foresters on the idea of using group selective felling. This idea was practically implemented later, and in the form not of group-selective felling, but of simplified, group-gradual felling. For the first time, group-gradual logging in the Buzuluksky forest was carried out in 1928 on an experimental basis, and in 1930 on a production scale. These fellings were carried out in four stages (Table 11) in mossy pine forests on more or less dry sandy soils.[ ...]

The Kostroma method gives good results if the young growth consists of self-seeding and small undergrowth up to 0.5 m high. In this case, up to 50-60% of it is preserved. If large undergrowth predominates, the damage rate is higher, and in this respect the Kostroma method is inferior, for example, to the methods used in some forestry enterprises in the Arkhangelsk region and Karelia, which allow preserving up to 70% of large and small undergrowth. The use of support trees is not always effective, and not only because of the height of the undergrowth. In low-productive thin-sized tree stands, they do not save even small undergrowth from damage during felling, so it is advisable to use them in highly productive forests.[...]

In these cases, almost more often the problem is to achieve the proper participation of coniferous undergrowth in the forest composition, since usually clear-cut areas here, as already indicated, are perfectly populated by birch, aspen, and alder, unless there is some admixture of them in the forest being cut down. [...]

During forced selective felling, it is not uncommon for growing trees to be damaged during felling and the undergrowth or felling of one tree when it hangs causes the need to cut down neighboring trees and the loss of the tree stand.[...]

In taiga clearings, according to V. Ya. Shiperovich, B. P. Yakovlev, A. A. Panov and others, the roots of coniferous undergrowth damage the root veins. As studies have shown recent years(V. Ya-Shiperovich, B. P. Yakovlev, E. V. Titova), in Karelia the most common and harmful are Siberian rootworms (Hylastes aterrimus Egg.) and spruce (Hylastes cimicularius Egg.). They cause damage mainly in the process of additional feeding, attacking healthy undergrowth and young spruce and pine trees. The greatest harm from them can occur in three- to five-year-old felling areas. According to E.V. Titova, in four- to six-year-old fellings, the number of young fir trees damaged by spruce roots reaches 90%, about 20% dry out completely.[...]

Finally, if viable young growth is preserved in sufficient quantities (2000-3000 pieces of coniferous undergrowth per 1 hectare), there is no need for artificial reforestation, which is expensive.[...]

Thinning in the first years of life of young animals, called lightening, consists of freeing the undergrowth of valuable species from being drowned out by minor impurities, regulating the relationships between specimens of undergrowth of the same tree species, and improving conditions for the growth of the best specimens of valuable species. The first thinning of young trees can be carried out before the introduction to the area main breed, an example of which is cutting corridors among elm, maple, linden, and hazel trees to introduce oak using Molchanov’s method.[...]

Seed groups, clumps, stripes. Using materials about the composition and structure of the forest stand, the placement of undergrowth and undergrowth, and places of possible undercuts, it is possible to pre-designate intra-cutting seed clumps and seed groups for abandonment. The area of the seed group usually occupies 0.01, less often 0.03 - 0.05 hectares. The area of the curtain reaches several tenths of a hectare, and sometimes reaches 1 hectare. In this regard, the danger of decay from the wind is greater for the seed group than for the clump. The seed group is a compact biogroup, which includes several ripening or ripe trees or undergrowth and thin trees.[...]

Pine is especially hard hit by snowbreakers, and aspen is the hardest hit among deciduous trees. Heaps of snow often damage young growth in forests and clearings. A measure to prevent snow breaker and snowfall is the timely thinning of excessively dense tree stands, the creation of forest forms with a loose crown canopy.[...]

The main condition for successful regeneration of spruce during selective felling is the preservation of self-seeding and undergrowth during felling and skidding of trees.[...]

After felling (in a wet blueberry spruce forest) using a technology that ensures a fairly high preservation of the undergrowth (50-60%), the formation of the sphagnum type of felling has a certain influence on the preliminary regeneration of the spruce. Thus, in 6-year-old fellings of this type (after the operation of the LP-19, LT-157 and Timbergek-360 machines) on an intact soil surface with preserved spruce regrowth (9.6 thousand pcs./ha, average age 18 years) The projective cover of herbaceous and shrub vegetation is 35-45%. The cover is dominated by sedge (15-20%) and blueberry (4-5%). Sphagnum moss occupies 20-30%, and green mosses - 5-7% of the area. In biogroups of spruce undergrowth, the cover of herbaceous and shrub cover is reduced to 15%. Here the participation of blueberries increases (up to 6-8%), green mosses (up to 15-20%) and the area occupied by sphagnum moss decreases (up to 15-20%). This regrowth has a positive effect on the subsequent regeneration of spruce. Consequently, the spruce undergrowth preserved during felling, which is a natural drainer, promotes the subsequent regeneration of spruce and somewhat inhibits the formation of sphagnum type felling. In the taiga forests of the European part of the USSR, the nature of sphagnum and sedge-sphagnum fellings and the regeneration of forests on them (formed after the work of traditional logging equipment) were studied by many researchers.[...]

In high-density (0.8 and above) spruce-deciduous, deciduous-spruce and deciduous stands with self-seeding and undergrowth of spruce, it is justified to carry out gradual felling in three stages with an intensity of initial reception from 25 - 30%, stock (in spruce-deciduous) - up to 35 - 45% (in deciduous-spruce and deciduous), in medium-density forest stands, cutting in two steps is advisable.[...]

It is more difficult to formalize the silvicultural and environmental assessment of the operation of logging equipment in cutting areas without undergrowth than in plantations with undergrowth. The complexity of solving this problem lies in the fact that we are dealing not with the real (before cutting), but with the future (subsequent) regeneration of the forest, which immediately after cutting is predicted with a certain reliability, based on the state of forest conditions in fragments of fresh fellings and emerging ones. on them parcels of plant communities in the presence of seed sources. Therefore, for an objective assessment of the operation of logging equipment, scientific data is needed for different ecological and geographical conditions on the nature of damage to the soil cover in connection with the use of one or another type of machines and technologies, on the nature of the emergence and development of parcels and types of fellings, on their impact on the emergence of seedlings and formation of self-seeding and undergrowth. Such data is available for a number of regions. Below is an assessment of the performance of aggregate logging equipment in clear-cutting in two different regions based on soil and climatic conditions. Thus, in the conditions of a lingonberry-ledum pine forest (Tyumen region) and a fresh blueberry spruce forest (Novgorod region) after the operation of LP-19 and LT-157 machines using a technology that involves laying trees at an angle to the drag, causing approximately the same area of soil damage (80-85%), the same reed-reed type of felling is formed with different forest conditions in each region. The duration of existence and features of the formation of this type in the two regions are different (Obydennikov, 1996). The occurrence of fragments of clearings with favorable conditions for the regeneration of the main species is, in the first case, in the conditions of a lingonberry-ledum pine forest, 72-77% (Tyumen region), in the second, in the conditions of a fresh blueberry spruce forest, 4-8% (Novgorod region). The given indicators, judging by the results of the studies, correspond to the actual occurrence of undergrowth of subsequent renewal in the presence of testes.[...]

To ensure good reforestation, appropriate care of valuable, economically important undergrowth is necessary - weeding and cutting down undergrowth and undergrowth of low-value species. Ignoring these measures was one of the main reasons for the unsuccessful use of gradual logging in pre-revolutionary Russia. Forest owners or officials usually tried to get forest regeneration without any significant monetary costs, often relying only on regulating the procedure for cutting down forests. Therefore, for example, as a result of ten years of experience in using gradual felling in the Sarapul district of forests of the Specific Department, according to a special survey by Danilevsky, it turned out that the vast majority of cutting areas in pine forests resumed unsatisfactorily and only 10-20% of all fellings resumed well. A survey of gradual cutting sites in the spruce forests of the Lisinsky forestry, carried out by D. M. Kravchinsky, showed that without caring for undergrowth, the regeneration of spruce turned out to be almost the same as in clear cuttings, namely, with the dominance of deciduous species (with a change of species) , against which the gradual felling was directed. D. M. Kravchinsky himself noted that in high-productivity spruce forests, the regeneration of spruce during gradual felling is hampered by the development of cereals (mainly reed grass) and undergrowth (mainly rowan) in the cutting area.[...]

In the lichen forests of the Arkhangelsk region, under the canopy, there are large quantities of strongly suppressed (sticky) pine undergrowth, which, after felling, quickly adapts to new conditions. Already 6-8 years after felling, such undergrowth differs little from pine trees that grew in the clearing. Only on the pre-cutting part of the stem are many young branches formed (from dormant axillary buds) (Fig. 15). Small-growing, strongly oppressed. Undergrowth is well preserved (84%) from damage during winter logging - even on portages with a single passage in summer time tractor TDT-40, viable specimens of undergrowth were preserved (Listov, 1986).[...]

Foresters were not satisfied with the relationship of tree species to light, established by the density of foliage and the nature of the crown, by the speed at which trunks are cleared of branches, and by the ability of undergrowth species to survive under the shade of the upper tiers of tree stands. They tried to move experimentally to the quantitative expression of the degree of light-loving and shade-tolerance by other methods.[...]

The regeneration of pine in concentrated fellings depends on the time elapsed after the fire (Fig. 16). As the age of the fire increases to 20 - 25 years, the amount of self-seeding and regrowth of pine increases sharply. In areas where there was a fire 30 - 40 years ago, the amount of self-seeding and undergrowth decreases as a result of the transition of part of it to the polewood stage, but still remains significant. Restoration is also proceeding successfully in areas with a longer fire duration (up to 40 - 60 years), although the amount of self-seeding and undergrowth continues to decrease. In areas where there were no fires or where they occurred more than 100 years ago, pine regeneration is usually less successful.[...]

Widely used in a number of enterprises Western Siberia(in particular, at the Komsomolsky and Sovetsky lumber mills in the Tyumen region) a technological scheme was found that preserves undergrowth (when installing two timber hauling mustaches, Fig. 31). According to the scheme, the LP-19 feller-buncher and chokerless skidders (LT-157, LT-154, etc.) are used. Before cutting the forest, two logging trucks and two loading platforms are installed at opposite ends of the cutting area. The LP-19 machine produces forest felling in strips (the width of each strip is 15 - 16 m).[...]

Thus, silvicultural requirements for technological processes during logging are usually established based on the direct impact of logging equipment on the soil and undergrowth at the time of logging or on changes in forest conditions in fresh fellings without taking into account the emerging types of clearings and forest regeneration in connection with them. In addition, there are no scientifically based acceptable limits for the preservation of undergrowth and the size of the damaged soil surface with different densities. upper layers. This leads to difficulty in objectively assessing the performance of logging equipment and its environmental consequences. The mentioned methodological approach to substantiating the criteria for silvicultural and environmental assessment of the operation of logging equipment is based on the use of cause-and-effect relationships between the input and output parameters of forest ecosystems and inter-level connections of plant parcels and biogeocenoses using the indicator of the occurrence of undergrowth. Of particular importance for establishing criteria are input indicators (preservation of undergrowth, degree of soil mineralization, density of its upper layers), which significantly influence the output of the ecosystem - types of felling, initial and subsequent stages of forest types. In areas with mature forest, depending on the method of regeneration after logging, different requirements are imposed on technological processes. The basis for classifying forest areas before logging to certain methods of regeneration (natural, preliminary and subsequent, artificial) after logging can be the amount of occurrence of undergrowth before logging or the likelihood of the formation of types of clearings with favorable or unfavorable conditions for the regeneration of the main species. Silvicultural and environmental requirements during the operation of logging machines in stands with undergrowth are imposed mainly on the occurrence of undergrowth (its other characteristics: density, viability and others are classified as restrictions), since this indicator is a reliable criterion for assessing the natural regeneration of the forest, allowing one to predict the composition and productivity of forest stands. The acceptable preservation of undergrowth is established by the ratio of the occurrence of preserved undergrowth under the forest canopy before felling and the occurrence of preserved undergrowth, according to which forest regeneration is assessed satisfactorily. Silvicultural and environmental requirements for the operation of logging machines in cutting areas without undergrowth are different. They depend on the method of regeneration after felling, i.e. taking into account the likelihood of the formation of one or another type of clearing and the forecast of the occurrence of undergrowth.[...]

For satisfactory regeneration of pine and larch stands on poor dry soil (in heath forests, lingonberries and similar ones), the preservation of a significant amount of undergrowth, numbering in the thousands per 1 hectare, is required. To regenerate a spruce or spruce-fir stand on fresh and moist soils (in sorrel and blueberry forests), it is often sufficient to preserve several hundred pieces of spruce and fir undergrowth per 1 hectare, if it is only more or less evenly distributed over the area.[... ]

As for ash, in its youth it is indeed more shade-tolerant than many of the species with which it grows in our forest-steppe mixed stands. Observations in these forests have shown that ash undergrowth actually often prevails over self-seeding oak and undergrowth of other species, despite the shading from above, often with three tiers (Krasnopolsky, A.V. Tyurin).[...]

Trees are felled with their tops in the direction of the movement of the fire. Branches cut off from trees are carried into the forest in the direction from which the fire is coming, and sections of cross-cut trunks are dragged in the direction opposite to the movement of the fire. Living cover, undergrowth and undergrowth are removed from the middle part of the breaking strip. The humus layer turns over, exposing the soil to the mineral layer.[...]

In place of wet blueberry spruce forest, immediately after felling, sphagnum, rush-pike and pike types of fellings are formed. The first is formed when there is damage to the soil surface on 35-40% of the cleared area and sufficiently high preservation of the undergrowth (up to 60%). This type passes into the lanceolate reed-sphagnum forest, and then into the moist blueberry spruce forest. The rush-pike and pike types of clearings are formed with significant soil compaction (usually 1.3 g/cm3 or more in the upper layer) and are most often confined to places near loading areas and logging slopes. In clearings of these types, conditions for the regeneration of spruce are extremely unfavorable, and for deciduous trees (mainly downy birch) - difficult.[...]

The disadvantages of preliminary regeneration are unevenness in the width and structure of the annual layers of wood before and after felling, and the subsequent increased knottiness and curvature of the trunks. These shortcomings, especially the knotty nature, are more associated with adolescents who have experienced prolonged oppression before logging. With severe suppression of undergrowth, the annual layers are not only narrow (from hundredths to several tenths of millimeters), but often fall out altogether, and a heeling of the trunk develops.[...]

The plots are divided into apiaries with a width equal to average height tree stand, with a minimum trail width of 4 - 5 m. Development of the apiary begins from the near ends. Felling trees with their tops on a drag below acute angle to it, so they do not have to be unfolded when pulling them out. The undergrowth is preserved in the amount of 70-75% more or less evenly over the entire area of the strips. With this method, small and large undergrowth is well preserved. Working conditions made it possible to reduce the composition of small complex teams by 1 - 2 people. Labor costs for chokering and skidding over the tops in the summer are 6 - 7% higher than for choking and skidding over the butts. However, the costs are offset by savings in reducing the labor intensity of clearing cutting areas, since with this method the branches are concentrated on the drags.[...]

The first way has become more widespread. Over the past three decades, many different technological schemes for the logging process have been proposed. The ideal is still far away, but there is some progress - a number of schemes ensure the preservation of regrowth up to 60 - 70%. However, this goal is becoming less and less achievable due to the introduction of powerful logging machines, which increase the impact on the forest and forest environment. First of all, the impact of such machines as VTM-4, VM-4A, LP-49, etc., affects the soil. Its compaction, strong exposure and movement, erosion and depletion are observed, undergrowth is destroyed and damaged, and injuries are caused to the roots and trunks of trees. During clear cuttings, this can lead to the formation of types of clearings that are unfavorable for forest regeneration.[...]

Fricke fell into such a gross mistake when he came out with a categorical objection to the division of tree species into shade-tolerant and light-loving as a “scientifically unfounded dogma.” The basis for Fricke’s speech was a special experience that involved freeing undergrowth under the forest canopy from “root competition.” But this experience in itself only proves that the success of the growth and development of undergrowth depends not only on lighting conditions, but also on the conditions of soil nutrition, which in turn is a condition for air nutrition of plants.[...]

The introduction of air-suspended skidding means (Fig. 109), rational trays (Fig. PO), regulation of the direction of tree felling using technical devices (wedges, etc.), prohibition of clear felling on steep slopes, transition to regulated selective and gradual felling - Here is an incomplete list of means for preserving iodrosga in mountain forests. To this we must add much that applies to lowland forests, for example, the use of snow cover to protect self-seeding and undergrowth from damage.[...]

In clearing areas, the composition and especially the number of fauna change. In the first years after logging in the spruce forests of the Arkhangelsk region, the number of squirrels decreases and disappears pine marten, birds of the Galliformes order. At the same time, the number of mouse-like rodents, stoats and foxes increases. The productivity of hunting lands, decreasing noticeably in the first years after logging, then increases as afforestation occurs and after 20 years becomes higher than the productivity of spruce forest lands. Clear cuttings are expanding the range of moose, hare and black grouse. The preserved undergrowth and the remaining seed clumps increase the hunting value of the clearings. Concentrated logging promotes the movement of the cockchafer to the north. Currently, it is widespread throughout the forest zone of the European part of the country and causes damage to crops and the natural regeneration of pine. This is due to favorable conditions for the May beetle: light and thermal conditions, penetration of the soil of clearings, the presence of herbaceous and other plants, the roots of which provide good and accessible food for young May beetle larvae. Grass cuttings (reed type) and some types of firewood are especially favorable for it.[...]

The natural regeneration of concentrated clear-cutting areas, as shown by numerous studies (Department of General Forestry of the LTA named after S. M. Kirov, Arkhangelsk Forestry Engineering Institute, Central Scientific Research Institute of Forestry, Northern Forest Experimental Group, Institute of Forest of the USSR Academy of Sciences, etc.), takes place in many areas of the taiga zone successfully, but mainly in hardwoods. In other types of forests, the participation of conifers in the regeneration of cutting areas is rare and is mainly due to the undergrowth remaining after logging and the slow appearance of self-seeding pine and spruce under the canopy of deciduous trees, which usually populate the cutting area in the first years after logging.

Introduction. The study of natural regeneration is of particular importance in afforestation. Such studies make it possible to determine the quantity and quality of the young generation replacing the maternal tree stand. Of great interest is the establishment of the sustainability of stands dominated by Scots pine.

The current growth of young trees is an objective indicator for assessing the condition of the undergrowth, since the forest stand can have both negative and positive effects on it.

It is known that the quantity and quality of undergrowth under the forest canopy largely depends on the species composing the forest stand. The advantage of natural regeneration from the point of view of biology and economics was emphasized by G.F. Morozov.

Weiss A.A. found that as the plant grows, the influence of trees on each other increases.

Iteshina N.M., Danilova L.N., Petrov L.V. determined that pine stands of natural origin have lower growth rates compared to artificial plantings.

The main sources revealing the issues of morphological relationships that affect both the growth and condition of plantings were the works of Weiss A.A. .

The purpose of the study was to assess the growth of young animals in height under the canopy and in the open.

Objects and research methods. The research objects were located on the territory of the Usinsk forestry. For the research, forest areas with density of 0.4, 0.7 and an open place were selected.

The work was carried out at the end of the growing season - in September. A total of 3 trial plots were established. On each trial plot there were 30 experimental plots of 1*1 m, where a selective census of pine undergrowth was carried out (seedlings were not taken into account) with the measurement of linear indicators. On selected sample plots, measurements of increments, age by whorls, height measurements, crown diameter and trunk diameter of Scots pine undergrowth were carried out in different lighting conditions (tree stands of different densities).
The annual height growth of 131 pine undergrowth was measured on 3 trial plots.

Experimental studies. The growth of trees in pine forests is the most important taxation indicator of both an individual tree and the entire forest stand. With the help of growth, it is possible to evaluate the potential productivity of a forest stand, the quality factor of growing conditions, and the competitive relationships between the components of plantings.

The current growth of young Scots pine trees is an objective indicator that characterizes their growth and condition, and also synthesizes the results of the vital activity of the plant organism.

To identify the growth of young trees in height in order to separate the undergrowth formed under the influence environmental factors graphs of growth by year and growth taking into account age were constructed. These graphs are shown below.

Figure 1. Dependence of the growth of young trees by year

Having analyzed the graph of growth by year, we can say that in open areas the minimum increase in undergrowth was observed in 2008, and the maximum increase was recorded in 2011. We can also say that the average increase varies within 7 cm. Under the canopy of the tree stand, the minimum increase in undergrowth was observed in 2000 and 2003, the maximum increase in 2005. The increase in height of pine undergrowth over the years in absolute terms showed its dynamism. Changes in growth within the trial plot may vary across all years, or be similar in individual years (Fig. 1).
These changes in the growth of Scots pine can be explained by the fact that in different years climatic factors had different effects on the growth of Scots pine undergrowth.

Figure 2. Dependence of adolescent growth on age

From the graph of growth depending on age, it can be seen that in an open place, with increasing age, growth increases (direct dependence). The minimum growth in adolescent growth was observed at the age of 4 years, the maximum at 10 years. In an open place, the growth rate is greater, the larger the undergrowth. Under the forest canopy, minimal growth was observed at the age of 8 years and increased sharply at the age of 9 years. Under the canopy there is no strict pattern as in an open place, since growth under the canopy big influence have limiting factors (light, nutrients, flow and pressure of the environment, soil, fires, microenvironment, etc.).

In a state of self-sowing, young trees have an underdeveloped root system and a small leaf surface. As the roots and leaves grow, the assimilating capacity of the crowns increases, and wood growth increases. Poor growth of pine undergrowth under the canopy of mature stands is due not only to a lack of light, but also to the fact that the trees of the mother stand intercept nutrients and moisture from the soil with their powerful and well-developed roots. The vital activity of the roots is significantly affected by the water located on the illuvial horizon, which most often appears in the spring after the snow melts. When it is high, the vital activity of the roots is delayed, the duration of the growing season is reduced and, as a result, growth is reduced. Pine is a light-loving species and grows well only without shading. Consequently, in an open place the growth rate is much higher than under a canopy.

Conclusion. Having studied the distribution of young animals by age and by year in an open place and under a canopy, the following conclusions can be drawn:

In an open area, the minimum increase in undergrowth was observed in 2008, and the maximum increase was detected in 2011;

Under the canopy of the tree stand, the minimum increase in undergrowth was observed in 2000 and 2003, the maximum increase in 2005;

The amount of growth within the trial plot may vary across all years, or be similar in individual years;

In an open place, the growth rate is greater, the larger the undergrowth;

Under the canopy there is no definite pattern as in an open place, since growth under the canopy is greatly influenced by limiting factors (light, nutrients, flow and environmental pressure, soil, fires, microenvironment, etc.);

In an open place, the growth rate is much higher than under a canopy.

Bibliography

Anhalt E.M., Zhamurina N.A. Analysis of the growth of pine undergrowth and young growth in pine-ash crops [Text] // News of the Orenburg State Agrarian University. 2013. No. 6 (44). P. 31-34.
Morozov G.F. Selected works / Moscow: Forestry Industry, 1971. 536 p.
Weiss A.A. Dynamics of competitive relationships: between tree individuals in a pine cenosis [Text] // Bulletin of KrasGAU. 2011. No. 5. P. 84-87
Iteshina N.M., Danilova L.N., Petrov L.V. Growth and structure of pine stands in various forest conditions [Text] // Innovative development of the agro-industrial complex and agricultural education - scientific support: Materials of the All-Russian scientific-practical conference. 2011. T.1. pp. 265-267
Weiss A.A. Dynamics of competitive relationships between tree individuals in a pine cenosis [Text] // Bulletin of the Krasnoyarsk State Agrarian University. 2011. No. 5. P.84-87.
Weiss A.A. Relationship between the diameters of the lower part of the trunks of Scots pine (Pinus sylvestris L.) in the conditions of Central Siberia [Text] // Forest taxation and forest management. 2011. No. 1-2. P.29-32.
Weiss A.A. Patterns of relationship between the diameters of Siberian larch trees (Larix sibirica) at chest height and diameters at stump height in conditions of central and southern Siberia [Text] // Bulletin of the Adygea State University. Series 4: Natural, mathematical and technical sciences. 2011. No. 1. P. 53-60.
Machyk M.Sh., Weiss A.A. Assessment of the progress of growth of morphological parameters of young pine trees, taking into account their age structure in the conditions of the East Tuva-South Baikal mountain forest region [Text] // Modern scientific research and innovation. 2016. No. 1 (57). From 268-276.

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Growing conditions

Number of spruce shoots

Under the treetops

Between crowns
(on a layer of moss)

Young trees that appear naturally in the forest are called undergrowth. They grew from seeds that fell on the surface of the soil. However, not every tree is classified as undergrowth, but only relatively large ones - from one to several meters in height. Smaller trees are called seedlings or self-seeding.

Undergrowth, as we know, does not form a separate layer in the forest. However, it is located for the most part at the level of the undergrowth, although sometimes higher. Individual specimens of undergrowth can vary greatly in height - from short to relatively large.

There is almost always some amount of undergrowth in the forest. Sometimes there is a lot of it, sometimes there is little. And it is often located in small clusters, clumps. This happens especially often in an old spruce forest. When you come across such a clump in the forest, you notice that it develops in a small clearing, where there are no trees. The abundance of undergrowth is explained by the fact that there is a lot of light in the clearing. And this favors the emergence and development of young trees. Outside the clearing (where there is little light), young trees are much less common.

Small clusters are also formed by oak undergrowth. But this is noticeable in the case when mature oaks are found in the forest alone among the total mass of other trees, for example, birches and spruces. The arrangement of young oak trees in groups is due to the fact that acorns do not spread to the sides, but fall directly under the mother tree. Sometimes young oak trees can be found in the forest very far from the mother trees. But they do not grow in groups, but one at a time, since they grew from acorns brought by a jay. The bird stores acorns, hiding them in moss or litter, but then does not find many of them. These acorns give rise to young trees located very far from adult fruit-bearing oaks.

In order for regrowth of a particular tree species to appear in the forest, a number of conditions are necessary. It is important, first of all, that the soil receives seeds and, moreover, benign ones that are capable of germinating. There must, of course, be favorable conditions for their germination. And then certain conditions are required for the survival of the seedlings and their subsequent normal growth. If some link is missing in this chain of conditions, then the undergrowth does not appear. This happens, for example, when conditions for seed germination are unfavorable. Imagine that some small seeds fell on a thick layer of litter. They will first begin to germinate, but then die. Weak roots of seedlings will not be able to break through the litter and penetrate into the mineral layers of the soil, from where plants take water and nutrients. Or another example. In some area of the forest there is too little light for the normal development of undergrowth. Shoots appear, but then die from shading. They do not survive to the teenage stage.

In the forest, only a very small proportion of seeds that fall to the ground give rise to seedlings. The vast majority of seeds die. The reasons for this are different (destruction by animals, decay, etc.). But even if seedlings have appeared, not all of them subsequently turn into regrowth. A lot can interfere with this. It is not surprising that our trees produce huge quantities of seeds (for example, birch many millions on one hectare). After all, only with such a strange, at first glance, extravagance is it possible to leave offspring.

In a forest, it often happens that one species dominates in the tree layer, and a completely different species dominates in the undergrowth. Pay attention to many of our pine forests that are quite old. There is absolutely no pine undergrowth here, but spruce undergrowth is very abundant. Often young fir trees form dense thickets over a large area in a pine forest. Young pine trees are absent here for the reason that they are very light-loving and cannot withstand the shading that is created in the forest. In nature, pine regrowth usually appears en masse only on open places, for example, in fires, abandoned fields, etc.

The same discrepancy between mature trees and young trees can be observed in many birch forests located in the taiga zone. Birch grows in the upper tier of the forest, and beneath it there is dense, abundant spruce growth.

Under favorable conditions, the undergrowth eventually turns into mature trees. And these trees of natural origin are more valuable from a biological point of view than those grown artificially (by sowing seeds or planting seedlings). Trees that have grown from undergrowth are best adapted to local natural conditions, the most resistant to various adverse environmental influences. In addition, these are the strongest specimens that have survived the harsh competition that is always observed between trees in the forest, especially at a younger age.

So, undergrowth is one of the important components of the forest plant community. Under favorable conditions, young trees can replace old, dead trees. This is exactly what happened in nature for many centuries and millennia, when the forest was little affected by humans. But even now, in some cases, it is possible to use undergrowth for the natural restoration of cleared forest or individual large trees. Of course, only when the young trees are sufficiently numerous and well developed.

Our story about forest plant communities has come to an end. You could see that all tiers of the forest, all groups of plants and, finally, individual plants in the forest are closely related to each other and, to one degree or another, influence each other. Each plant occupies a specific place in the forest and plays one or another role in the life of the forest.

There are many remarkable features in the structure and life of forest plants. They will be discussed further. But to make the story more consistent and clear, we divided the material into separate chapters. Each chapter looks at plants from a different perspective. One chapter talks about interesting structural features, another - reproduction, the third - development, etc. So, let's get acquainted with some of the little secrets of plants living in the forest.

But first, a few more words. The book consists of separate short stories, unique biological sketches. These stories will talk about a variety of forest inhabitants - trees and shrubs, herbs and shrubs, mosses and lichens. It will also be said about some mushrooms. According to the latest ideas, mushrooms are not classified as flora, but are allocated to a special kingdom of nature. But the greatest attention will, naturally, be paid to trees - the most important, dominant plants in the forest.

It should also be noted that our story will concern not only plants as a whole, but also their individual organs - both aboveground and underground. We will get acquainted with the interesting biological secrets of flowers and fruits, leaves and seeds, stems and rhizomes, bark and wood. In this case, attention will be paid mainly to large external signs that are clearly visible to the naked eye. Only here and there we will have to touch a little on the internal, anatomical structure of plants. But here we will try to show how different microscopic features are reflected in external signs- on what is visible to the naked eye.

And one last thing. The division adopted in the book into separate chapters devoted to certain characteristics of forest plants (structure, development, reproduction) is, of course, conditional. This was done only for convenience of presentation, for some ordering of the material presented. There are no sharp demarcations between these chapters. It is difficult to draw, for example, a clear boundary between structural features and reproduction. The same material can be placed with almost equal rights in either one or the other chapter. For example, a story about special structure seeds of pine and spruce, allowing them to rotate very quickly in the air when falling from a tree, concerns both structure and reproduction. In the book, this material is placed in a chapter devoted to the structure of plants. But this is just an arbitrary decision of the author, which I hope the reader will forgive him, just like some other similar decisions.

According to OST 56-108-98, the following terms are distinguished:

Seedlings are plants of tree species up to one year old, formed from seeds.

Self-seeding is young woody plants of natural seed origin at the age of two to five, and in northern conditions up to ten years.

The undergrowth is the young generation of the forest, capable in the future of entering the upper tier and taking the place of the old forest stand, under the canopy of which it grew. Undergrowth refers to the generation of woody plants older than two to five years, and in the conditions of the North - older than ten years, before the formation of young growth or a layer of the forest stand.

Young growth includes viable, well-rooted trees of the main species with a height of more than 2.5 m and a diameter at breast height below the release diameter established in the regional logging rules, capable of participating in the formation of a stand, and therefore the logging of such trees is prohibited.

The undergrowth can be of seed or vegetative origin.

Seed reforestation is considered the most advanced, allowing new generations of trees, as a result of the splitting of characteristics, to successfully improve in response to a changing environment.

Vegetative regeneration, in its essence, is an absolute copying of the properties of the parent organism with the absence of genetic differences. This reduces the adaptive abilities of the new generation of such plants. Among tree species, almost all deciduous trees renew themselves vegetatively, unlike conifers. In this case, new individuals appear from the vegetative organs of the parent plant: dormant and adventitious buds on the trunk, branches, roots. This ability is used in forestry to propagate particularly valuable clones or individual specimens. The formation of adventitious roots on shoots of conifers in a natural environment is a rare phenomenon. Therefore, vaccinations are used for their vegetative propagation.

The process of accumulation of undergrowth under the canopy of a tree stand is called preliminary regeneration, i.e. renewal that occurs before the forest is cut down (before its death). The undergrowth under the canopy is called pregeneration undergrowth

Regeneration that occurs after forest cutting is called subsequent. Accordingly, the undergrowth that appears after felling is called undergrowth of the subsequent generation.

The undergrowth of all tree species is divided into:

· in height - into three categories of size: small up to 0.5 meters, medium - 0.6-1.5 meters and large - more than 1.5 meters. Young animals to be preserved are counted together with large juveniles;

· according to density - into three categories: rare - up to 2 thousand, medium density - 2-8 thousand, dense - more than 8 thousand plants per hectare;

· by area distribution - into three categories depending on occurrence (the occurrence of undergrowth is the ratio of the number of counting plots with plants to the total number of counting plots laid out in a trial plot or cutting area, expressed as a percentage): uniform - occurrence over 65%, uneven - occurrence 40-65%, group (at least 10 small or 5 medium and large specimens of viable and closed undergrowth).

Viable undergrowth and young growth of coniferous forest plantations are characterized by the following characteristics: dense needles, green or dark green color of needles, noticeably whorled, pointed or cone-shaped symmetrical dense or medium-density crown extending at least 1/3 of the trunk height in groups and 1/2 trunk height - with a single placement, height growth over the last 3-5 years has not been lost, the growth of the apical shoot is not less than the growth of the lateral branches of the upper half of the crown, straight undamaged stems, smooth or fine-scaly bark without lichens.

Undergrowth and young growth of coniferous forest plantations growing on dead wood can be classified as viable according to the indicated characteristics if the dead wood has decomposed and the roots of the undergrowth have penetrated into the mineral part of the soil.

Viable undergrowth of hardwood forest stands is characterized by normal foliage of the crown and stems proportionally developed in height and diameter.

Paragraph 51 of the Timber Harvesting Rules states “When felling mature, overmature forest plantations, the preservation of undergrowth of forest plantations of economically valuable species in areas not occupied by loading points, highway and apiary trail routes, roads, production and domestic sites is ensured, in an amount of at least 70 percent when carrying out clear cuttings, 80 percent when carrying out selective cuttings (for mountain forests - 60 and 70 percent, respectively).”

In connection with this requirement, if there is a sufficient amount of viable undergrowth, the technological map for the development of a cutting area indicates the need to preserve it throughout the entire area of the cutting area or on parts of it if the undergrowth is arranged in clumps. Felling of undergrowth is permitted:

· when cutting sights;

· when cleaning hanging and dead trees;

· on the territory of upper warehouses and loading points;

· on logging roads;

· on skidding roads;

· in places where mechanisms are installed;

· during mechanized felling of trees within a radius of up to 1 m from the tree being felled;

· on routes up to 3 m long to allow the feller to move away from the tree.

Clauses 13 and 14 of the Reforestation Rules read:

Measures to preserve the undergrowth of forest plantations and valuable forest tree species are carried out simultaneously with the felling of forest plantations. In such cases, felling is carried out mainly in winter on snow cover using technologies that make it possible to ensure that the amount of undergrowth and young growth of valuable forest tree species is not less than that provided for during the allocation of cutting areas from destruction and damage.

During felling of forest plantations, viable undergrowth and young growth of pine, cedar, larch, spruce, fir, oak, beech, ash and other forest plantations of valuable species must be preserved in their corresponding natural and climatic conditions.

The undergrowth of cedar, and in mountain forests also the undergrowth of oak and beech, are subject to recording and preservation as the main species for all logging methods, regardless of the quantity and nature of its distribution over the cutting area and the composition of the forest stand before felling.

To protect the undergrowth of the main forest tree species from unfavorable environmental factors in clearing areas, more successful growth and the formation of forest plantations of the required composition, the undergrowth of accompanying forest tree species (maple, linden, etc.) and shrub species are fully or partially preserved.

In pine forests growing on sandy loam soils, the regrowth of spruce forest plantations is preserved provided that the spruce plantation does not reduce the quality and productivity of the forest stand. When restoring pine and spruce forest plantations, undergrowth is, if necessary, retained in the felling to protect the soil and form stable and highly productive pine and spruce forest plantations.

Undergrowth affected by pests, underdeveloped and damaged during logging must be cut down at the end of logging work.

When carrying out selective felling, all undergrowth and young growth under the forest canopy are subject to recording and preservation, regardless of the number, degree of viability and the nature of their distribution over the area.

To determine the amount of undergrowth, conversion factors from small and medium undergrowth to large undergrowth are used. For small undergrowth, a coefficient of 0.5 is applied, for medium-sized ones - 0.8, for large ones - 1.0. If the undergrowth is mixed in composition, regeneration is assessed based on the main forest tree species, corresponding to natural and climatic conditions.

Counting of undergrowth and young animals is carried out using methods that ensure the determination of their number and viability with an accuracy error of no more than 10 percent.

In all cases, it is necessary to maintain predetermined distances between sites on the sights and counting tapes. On plots of up to 5 hectares, 30 registration plots are laid out, on plots from 5 to 10 hectares - 50 and over 10 hectares - 100 plots.

Currently, it is believed that of all the measures to promote natural reforestation, the most effective is the preservation of undergrowth, i.e., the emphasis is on preserving the results of preliminary reforestation. To preserve undergrowth, special methods of wood harvesting have been developed (“Kostroma method” with mechanized felling, shuttle method when working with VTM, etc.), which make it possible to preserve up to 65% of the undergrowth available in apiaries, but at the same time significantly reducing the productivity of the main work.

Preservation of undergrowth and young growth during logging ensures economic restoration of forests in cleared areas valuable species and prevents undesirable change of species, shortens the period of forest restoration and the time of growing technically mature wood, reduces the costs of reforestation work, and contributes to the preservation of the water protection functions of forests. IN scientific literature, for example, in the works of prof. V.N. Menshikov, there is information that this method of promoting reforestation can reduce the turnover of cutting the main species by 10–50 years.

However, as practice shows, a primary focus on preserving adolescence is not always justified for the following reasons:

· on most of the forested flat lands of the forest fund of the Russian Federation, the main species are conifers;

· in forests where light-loving conifers (pine, larch) are chosen as the main species, the regrowth of these species is almost absent due to their inability to develop normally under the maternal canopy;

· in forests formed by shade-tolerant conifers (spruce, fir), there is a large amount of undergrowth, however, according to our observations and according to other researchers, a large amount of undergrowth preserved during logging dies in the first 5–10 years after clear cutting due to a sharp change in the microclimate and light regime after removal of the maternal canopy (burning the needles and root collar, squeezing the roots, etc.). Moreover, the percentage of dying undergrowth directly depends on the type of felling, and, consequently, on the type of forest that preceded it;

· the undergrowth dying off within 1–2 classes of age litters the cutting area, increasing its fire hazard and increasing the risk of forest damage by pests and diseases.

In connection with the above, it can be argued that in certain types of forest, when focusing on natural forest regeneration, refusal to preserve undergrowth, with the obligatory abandonment of sources of contamination, can give more positive than negative results for the following reasons:

· logging technologies without preserving undergrowth are more productive than technologies with its preservation;

· rejection of a strictly defined network of apiary skidding tracks means that the load work of skidding routes (one track) can be significantly reduced (depending on the distance from the upper warehouse, the forest stock per hectare and the carrying capacity of the skidding tractor), which will contribute to the improvement of forest soil due to its mineralization, as well as bringing the soil density to optimal for seed development, i.e. improving conditions for subsequent natural reforestation);

· when clearing cutting areas from logging residues, it becomes possible to use high-performance rake-type pick-ups;

· refusal to preserve undergrowth will allow wider use of tree skidding technology, sharply increasing the productivity of the operation of clearing trees from branches (using mobile delimbing machines), will allow concentrating most of the logging residues in the upper warehouse, significantly facilitating their further disposal and reducing the labor intensity of cleaning cutting areas.

A number of scientific publications devoted to the success of natural reforestation note that in clearings in Western and Central Siberia, 15–95%, and sometimes 100% of the preserved viable coniferous undergrowth perishes. The same data were obtained on some types of clearings for the conditions of the North-Western region of the Russian Federation V.I. Obydennikov, L.N. Rozhin. They note that “the mortality of spruce undergrowth (20 years old at the time of felling) over a five-year period after clear felling (in the conditions of the Krestetsky private farm) amounted to 18.5% in the emerging forb-reed type of fellings, and 57% in the reed-reed type. 3%, in Sitnikovovoye – 100% .

In addition, as a result of large-scale studies carried out in the 80s of the twentieth century, it was found that in general in the North-West region the area of forest plantations with a sufficient amount of undergrowth of main species for sustainable reforestation does not exceed 49.2%, and in some areas it does not exceed 10% (Novgorod region - 9.0%, Pskov region - 5.9%).

The above facts allow us to assert that in large forest areas the preservation of undergrowth is unprofitable due to poor prospects for its development or its insufficient quantity. In this case, subsequent natural reforestation comes to the fore, based on the mandatory preservation of sources of seeding and supported by such assistance measures as soil preparation, cleaning of cutting areas, etc.

From the point of view of subsequent natural reforestation (germination of seeds that have fallen into the soil), the condition of the soil will be one of the main factors influencing the success of this process. It is also obvious that the use of machines and mechanisms to perform special technological operations to prepare the soil for natural reforestation will increase the cost and complexity of the logging process. Therefore, when carrying out logging operations, it is necessary to strive for such an impact on the forest environment, in particular on the soil of the cutting area, which would provide optimal conditions for subsequent reforestation.

This approach is reflected in the Timber Harvesting Rules, in paragraph 56 of these rules it is stated: “In lowland forests, with clear cuttings without preserving young growth in forest types where the mineralization of the soil surface has a positive impact on forest regeneration, the area of the trails is not limited. The types (groups of types) of forest where such logging is allowed are indicated in the forestry regulations of the forest district or forest park.”

At the same time, the regulatory documents do not yet provide more specific instructions in which cases it can be considered that the mineralization of the soil surface has a positive effect on reforestation.

Caring for a teenager

After the completion of logging operations during summer harvesting and after the melting of snow and thawing of the soil during winter felling, the preserved undergrowth is trimmed and cared for. Undergrowth and young growth are freed from logging residues, and the root systems of plants that have lost contact with the soil are pressed to the ground. Broken, shriveled and severely damaged specimens during the logging process are cut down and removed from apiaries or landed along with logging residues.

After the main mortality, after 2-3 years, shrunken, severely damaged individuals of the main species are removed, for example, those with stripped bark wider than 2 cm, undergrowth of undesirable species or their trees of subsequent renewal and shrubs that interfere with the growth of the main species. In the first year after felling, such work should not be carried out, because unwanted tree and shrub vegetation serves as protection for the undergrowth from the sun, frost, and wind, which increases evapotranspiration. Caring for young trees, as a measure of promoting natural reforestation, is especially necessary for light-loving species: pine, oak, larch.

Under conditions of normal moisture supply, reliable (light) undergrowth increases not only transpiration, but also photosynthesis, metabolism increases, and root respiration is activated, which contributes to the development of the root system and assimilation apparatus. It is important that from the buds laid under the forest canopy, needles are formed in clearings, which are close in anatomy and morphology to light ones. New needles also arise from dormant buds.

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