On the issue of logging in the taiga zone

. Objects of research: forests of the Arkhangelsk and Vologda regions within the boundaries of the taiga zone. The results of the study are of scientific and practical interest for organizing effective forest management and forest management. Currently, a significant share of clear-cutting occurs in the so-called pioneer development areas (for example, Leshukonsky district of the Arkhangelsk region). In these areas, the approach to forest management must be meaningful and scientifically based in order to prevent deforestation of the areas. Effective use of forests is required by optimizing cutting regimes and parameters, which will allow for intensive forestry with the cultivation of high-quality coniferous wood, ensuring a balance between deforestation and their reproduction with economically valuable species. The goal of the work is to improve the system of forestry activities in the forests of the taiga zone. The basis for the development of assessment indicators for the purpose of felling, their classification in the system of forest use and development, was the scientifically based results of many years of research at stationary objects. For each of the stationary objects, silvicultural requirements and indicators (criteria) were established and developed for the purpose of felling in plantations of different structure, structure, and origin. The status of felling in the classification and in the system of forest use has been established. The results are necessary for the development of forestry development programs in the Russian Federation as part of the implementation of the concept of intensive use and reproduction of forests.


Introduction
In the Strategy for the Development of the Forestry Sector of the Russian Federation until 2030, the country's forests are represented mainly by boreal forests, which occupy about 65% of the forest area and grow in harsh climate conditions, which causes high costs for timber harvesting and transportation [1].Problems of forest conservation and use are becoming more diverse and complex.The consequences of climate change, the threat of forest loss from fires, pests and other unfavorable factors, and the risks of forest loss of biological diversity are increasing [2][3][4][5][6][7][8][9][10], as indicated in the Russian Federation state program "Forestry Development" [11].

Materials and methods
The objects of study are the forests of the Arkhangelsk and Vologda regions within the boundaries of the taiga zone.The goal of the work is to improve the system of forestry activities in the forests of the taiga zone.
The research methodology included generally accepted silvicultural methods, including planting and taxation of plantings on trial plots, taking into account the requirements of OST 56-69-83 "Trial forest management plots.Bookmark methods."

Results and Discussion
An experimental plot of thinning (thinning) with a total area of 10 hectares was established in 2008 in the Arkhangelsk forestry (Arkhangelsk district forestry, quarter 36, issue 6) and is represented by an experimental variant and a control.Forest typelingonberry pine forest.The intensity of rarefaction in the experimental version in terms of reserve was 34%.During the thinning process, 548 m 3 of small commercial pine wood was harvested at the experimental site.After 15 years, repeated forest accounting work was carried out in the pilot version.
The dynamics of individual indicators over the research periods shows that, despite the age of thinning, differences in the average diameter and height on the site, with and without thinning, remain.Thinning caused a more significant increase in the average diameter of the pine stand compared to the control.The available stock of pine wood 15 years after thinning was 217, in the control -only 169 m 3 /ha.Thus, thinning led to a significant silvicultural effect by increasing the average annual growth in diameter, height and stock.After thinning on the experimental site, the optimal composition of the forest stand (10C+B) was formed from a silvicultural point of view.
The stationary facility "Chekshino" with a total area of 1.0 hectares is located on the territory of the Sokolsky forestry in the Vologda region (Dvinitsky district forestry, quarter 58, issue 2).Forest typeblueberry birch forest.The station is represented by 4 experimental options with complex felling and control (Figure 1).spruce in the amount of 8-10 thousand pcs./ha was selected.In the experimental variants, all deciduous wood was harvested in the winter, and in the summer (June-July) the logging sites were cleared and the undergrowth was thinned using a selective method, preserving spruce in an amount of 1.5; 3.0; 4.5 and 6.0 thousand pieces/ha (options I, II, III and IV, respectively).First of all, damaged spruce trees with a poorly developed crown and a weakened vital condition (depressed) were subject to felling, which interfered with the growth of selected, promising trees for subsequent growing, while maintaining a uniform distribution of undergrowth over the area.
In the experimental variants, as a result of complex felling, a pure in composition, simple, highly dense (relative completeness 1.22-1.57)spruce stand, characterized by high productivity (292-365 m 3 /ha), has now been formed.The available supply of spruce element in the experimental variants is 4.6-5.8times higher than in the control area.As a result of cutting down deciduous trees, active growth was observed in some of the subcanopy spruce specimens.During the first year after felling, rapid growth of undergrowth with an average height of 1.5-2.0m was observed in 10-20% of trees.As the age of felling increased, an increase in the growth rate of spruce was noted in all variants.As the results of the study show, on average, over the first 10 years after felling, the most active growth in height was observed in variants I and II.However, differences between sample means are proven only for options I -III, IV and II -III (tfact.t0.95).15 years after cutting, 50-60% of spruce trees adapted well to new environmental conditions, which affected their growth activity.This pattern was especially evident in option I with the smallest amount of spruce being preserved (1.5 thousand pieces/ha).In addition, in this variant there was a significant increase in the number of spruce undergrowth specimens due to the transition of self-seeding to this category.If we do not take into account the period of 1-2 years after felling (adaptation period), then the growth of the subcanopy spruce proceeded according to class I of the current quality.
Conducted studies of spruce undergrowth up to 4 m high, formed after felling, indicate that with a spruce density of 1.5 and 3.0 thousand pieces/ha, care is necessary for the first 10 years.In case of late arrival with fellings, when the height of the spruce element has exceeded 5-6 m (at the age of spruce 50-60 years), its significant decline is noted.To avoid the consequences of windfalls, it is necessary to ensure a relatively uniform structure of the upper canopy.Trees with a spreading crown or in a depressed state are subject to mandatory harvesting.
The formed spruce forests at the age of 45 years with an average height of 5-6 m corresponded to quality class V, at the age of 78 years -III-IV.The third grade was noted in spruce forests with the lowest density (variants I and II).It should be noted that initially the native spruce forest (before the formation of the birch forest) was characterized by quality class III.
In variants I and II, after complex felling, the spruce was distributed into 5 groups of altitudinal gradation, after 7 years their number increased to 8. Already 4 years after felling, a transition of undergrowth was observed in all selected altitude groups to the next altitudinal gradation, in some cases (according to medium and large teenagers)bypassing one or two steps.At the same time, the surplus portion of the undergrowth was replenished due to self-seeding.In variants III-IV, similar differentiation did not appear.In experimental variants III-IV, a transition of part of the undergrowth from lower levels to the next high-altitude category was noted, from middle levels -through one category, from large levels -through two categories.The process of emergence of self-seeding and seedlings is less pronounced, which was evident throughout the entire observation period.
In option I, that is, with a lower density of retained undergrowth, the spruce was distinguished by more intensive growth in height compared to other experimental options; the excess in average height 10 years after felling was 12.1-20.1%).The spruce in option III had the lowest growth rate in height.At the ages of 62 and 78 years (27 and 43 years after felling), spruce in variants I and II had the highest growth rates in height.
To date, variants I (20.0 cm) and II (17.5 cm) are characterized by the largest diameter at chest height.The excess diameter in option I compared to options II, III and IV was 1.1; 1.2 and 1.3 times respectively.
At the age of 78 years of spruce (43rd year of registration), the largest supply of wood was noted in option I (365 m 3 /ha), then in descending order of the indicator, the experimental options were arranged as follows: option III (358 m 3 /ha), option IV (351 m 3 /ha) and II (292 m 3 /ha).It should once again be especially noted that the formed forest stand in the experimental variants is characterized by high productivity in comparison with the control plot.
The results of studies performed at the stationary site are registered in the Database Register "Silviculture and taxation indicators of plantings after complex felling at the Chekshino stationary site."

Conclusion
For many decades, the Federal Budgetary Institution "Northern Research Institute of Forestry" has been engaged in theoretical substantiation and development of practical recommendations for forest management in forests of the taiga zone, their rational use and increasing productivity.At the same time, it is very important to test and implement their theoretical and practical developments, including all types of logging in derivative forests that formed on the site of clear concentrated logging of the 30-80s of the last century.The purpose of such scientific measures is the introduction of research results into forestry practice and the creation of objects for long-term observations of changes in the natural environment, resource and ecological components of forest ecosystems, the accumulation of natural materials for the ecological, silvicultural and economic justification of measures to intensify the use and reproduction of forests.These measures are consistent with the Strategy for the Development of the Forestry Sector of the Russian Federation until 2030, approved by the Government of the Russian Federation dated February 11, 2021, No. 312.

Fig. 1 .
Fig. 1.Experimental version I at the Chekshino stationary facility.The experimental facility was laid by V.F.Mole in 1979-1980.To set up the experiment, a highly dense (relative density 1.0) birch plantation (with a single participation of aspen and willow) of pyrogenic origin with the presence of subcanopy