Clear cutting. Clear cutting of forest plantations

3.1.1

Clear cutting (forestry)

More than one generation of foresters was brought up on the principle of G.F. Morozova " felling and renewal are synonyms" And nowadays, the forester must always remember that the ultimate goal of final felling should be to replace mature forest with a new generation.

The main comprehensive indicator of the use of clear cuttings is the silvicultural state of the undergrowth. With the same completeness of the upper layer, the viability of the undergrowth may be different. As age increases, the viability and prospects of adolescents decrease.

Clear cuttings for final use with preliminary (natural or artificial) regeneration are significantly different from fellings with subsequent renewal.

RGP with preliminary natural reforestation carried out in areas with tree stands, under the canopy of which there is economically viable undergrowth–valuable species, capable of adapting to dramatically changed conditions and forming a young forest during a single felling of a tree stand. Usually these are areas of the same age, low–and medium-density forest stands of coniferous, hard-leaved and soft-leaved species.

Clear cuttings with preliminary artificial reforestation have not found widespread use.

Clear cuttings with subsequent natural renewal carried out in groups of forest types where there is no undergrowth under the canopy and its appearance is problematic without human help. In this case, simultaneously with cutting down the tree stand, special measures are taken to promote forest regeneration (partial removal of litter, mineralization of the soil surface and its loosening, etc.), which ensures the regeneration of the target species. Basically, these are indigenous complex pine and spruce forests, oak groves and other types of forests where there is great competition with herbaceous vegetation, there is a high probability of regeneration of undesirable tree species (soft-leaved) or in the absence of sources of natural forest regeneration.

Due to significant silvicultural differences in clear cuttings of preliminary and subsequent renewal, at one time the following were distinguished: narrow–average – and wide cuttings.

According to the “Rules...” the clear-cutting system in the forests of the Republic of Belarus allows the use of:

Clear-cutting strip fellings with a cutting area width of up to 100 m with direct, less often inter-strip or side-by-side abutment;

Solid –precinct (or precinct) felling when felling individual taxation areas of up to 5.0 hectares in coniferous and hard-leaved forests and up to 10.0 hectares in soft-leaved forest stands.

Clear cuttings are carried out mainly in forests of group II. In forests of group I, clear felling is allowed:

In overmature, decaying plantings;

In plantations damaged by fires, pests, fungal diseases with progressive drying out of trees;

In low-density plantings;

In plantations where clear cuttings cannot be carried out due to the high danger of windfall;

In mature plantations, where it is impossible to ensure natural regeneration of the target species.

The cutting method is established for each specific area (taxation area, cutting area), taking into account, as noted above, forest conditions, composition, structure and current state of the planting, the presence of undergrowth or a second tier, the method of reforestation and the target species of the future planting, as well as the wind resistance of the remaining planting. parts of the forest stand and adjacent plantings. The cutting down of some plantings should not significantly affect the increase in the danger of windfalls for other remaining plantings. Otherwise, other cutting methods are used, and narrower (up to 50 m) cutting areas are allocated. Plantings that are not resistant to wind blows include spruce and aspen forests with a height of more than 23 m, pine and birch forests with a height of more than 25 m, growing on soils of normal moisture, as well as tree stands with a significant admixture of spruce (30-50 percent), with a height of more than 21 m on soils with increased moisture content. hydration.

The main organizational and technical elements (OTE) of clear-cutting are:

The width and shape of the cutting area, its area;

Cutting direction;

Direction of cutting area;

Method of joining cutting areas;

Deadline for joining cutting areas;

Technology of logging operations;

Method of cleaning cutting areas;

Reforestation activities.

The width and shape of the cutting area, its area. The width of the cutting area is the length of the cutting area along the short side. It is determined by the distance at which a sufficient number of seeds flies from the forest walls. They also take into account the influence of forest walls on changes in microclimatic and soil conditions, the degree of sodding of the felled area and the possibility of an undesirable change in species. It should be noted that when designing new methods of mechanized logging, the forester, first of all, strives to preserve the preliminary renewal of the main species.

The “Rules...” provide for the possible width of cutting areas (from 50 to 100 m) depending on the group of forests (Appendix P).

In a block with a side of 1 km in forests of group II with a cutting area width of up to 100 m, two cuttings are allowed, i.e. cutting areas of one year. If the quarter is smaller, one cut is allowed.

The shape of the cutting area is usually rectangular, and for small areas (up to 5 hectares in hardwood plantations, up to 10 hectares in coniferous forests and up to 25 hectares in softwood forests) it can correspond to the configuration of the plot.

The area of ​​cutting areas in group I forests for coniferous and hard-leaved trees is no more than 3 hectares and soft-leaved trees - no more than 5 hectares, and for group II forests - 5 and 10 hectares, respectively.

Cutting direction. The cutting direction is the direction in which the cutting areas are located one after the other. It always chooses to face the main danger (wind, water flow, erosion, etc.). In the conditions of the republic, the most dangerous are the western and northern–westerly winds, prevailing during the most dangerous times of the year in terms of wind blows. The cutting direction is the main one, and then, depending on it, the cutting direction is set.

Direction of the cutting area. This is the direction of the long side of the cutting area in relation to the parts of the world. It should facilitate seeding of the cutting area from the forest walls and provide more favorable conditions for seed germination, rooting of seedlings and further growth and development of self-seeding. The direction of the cutting area is always perpendicular to the direction of felling.

Method of joining cutting areas. This is the order of spatial placement of one cutting area relative to another. The abutment can be direct, interstriated, rocker and staggered. At direct At the junction, each subsequent cutting area is located next to the previous one. This is the most common method to ensure natural regeneration of the forest. At interstriped At the junction, the next cutting area is laid not next to the previous one, but through a strip of forest with a width equal to the width of the cutting area. The disadvantage of this method is the likelihood of massive windfall, and this is most often observed in spruce plantations on poor soils. At backstage at the junction, the remaining strip of forest is two or three times wider than the cut-down areas. Chess The adjoining of cutting areas is rarely used. Figure 2 shows the methods for connecting cutting areas.

The current “Rules...” establishes a direct method of joining cutting areas, although in special cases (in wind-resistant forest stands on fresh and dry soils) natural resumption of felling is ensured by strip and side-by-side joining. The length of the cutting area is determined by the size of the block or the length of the mature forest stand.

Deadline for joining cutting areas. This is the period of time after which felling is carried out at the next cutting site. The period of contiguity is set depending on the conditions for the resumption of felling and is usually equal to the period between two seed years. The year of felling during abutment is not included: this means that, for example, at 2–During the summer period, the cutting areas will be cut down in 2006, 2008. etc.

Subject to satisfactory resumption of the previous cutting area during clear-cutting, the “Rules..” establish the following deadlines for the adjoining of cutting areas: for soft-leaved forest stands - 1-2 years, for conifers and hardwoods – 3-4 years.

Direction of prevailing winds

Cutting direction

Left stripes (backstage)

Figure 2 – Junction of cutting areas:

1 – direct; 2 – interstrip; 3 – rocker; 4 – chess

(a – width of the cutting area; 1….19 – No. of cutting areas, 2001 –2037 – year of felling)

Source of contamination of clearings There may be individual trees, various groups of them, or forest walls that perform the seeding function. Seed trees are well-fruiting, wind-resistant trees with good growth and trunk quality, specially left behind during felling. Seed groups usually less than 0.01 hectares in area are left in the clearing for seeding. Seed clumps are separate stable parts of the tree stand, left in the clearing for its seeding, with an area of ​​0.01 to 1.0 hectares. Seed strips are left 30 wide -50 m.

All organizational and technical elements of clear-cutting strip felling that are being designed must be shown on the plan (scale 1:10000).

Technology for developing cutting areas includes the technology of felling, skidding, cleaning trunks from branches and loading wood. Logging is the movement of trees, logs (the trunk part of a tree without branches) or assortments (logs cut transversely into pieces of various sizes) from the felling site to a timber loading point or logging road. When drawing up a project for each site of final felling, the text indicates the system and type of felling, methods of skidding and cleaning of felling sites, locations of upper warehouses or loading areas, placement of roads, main and logging roads, as well as measures to preserve undergrowth at the cutting site.

The construction of loading platforms and skids is carried out in places where there is no undergrowth. The total area of ​​skidding roads and loading areas should be no more than 20 percent of the cutting area. The width of skidding roads should not exceed 5 m.

Currently, in practice, RGPs are used as single-operational ones (chainsaws “Husqvarna”, “Stihl”, “Solo”, skidders of the AMKADOR type–2200; MTZ –82; TTR –401; TTR – 402 and others), as well as multi-operational machines (harvesters and forwarders “Valmet”, “Hiab”, “Sisu”, “Timberjack”) of domestic and foreign production.

When selecting a system of machines and mechanisms and developing the most rational technological schemes for logging operations, it is recommended to use the “Guide to the organization and conduct of logging in the forests of the Republic of Belarus” (5).

Using the example of clear-cutting using the method of wide apiaries in the absence of reliable viable undergrowth, the design of the scheme for developing a cutting area is shown (Figure 3).

Figure 3 – Scheme for the development of cutting areas in the absence of reliable viable undergrowth using a gasoline-powered saw and skidding with tractors: 1 – logging trail, 2 – main drag, 3 – apiary drag, 4 – safety zone, 5 – tree felling, 6 – cutting off branches in the apiary, 7 – laying branches on a drag, 8 – skidding, 9 – growing trees, 10 – stumps from felled trees

The description of the technological process according to this scheme is approximately as follows. The loading point is located on the driest area of ​​the cutting area, taking into account the direction of removal, and the timber hauling point is located along the border of the cutting area. A safety zone with a width of at least 50 m is created around the loading point and along the logging fence. When developing cutting areas using the wide apiary method (35-45 m) in the absence of reliable viable undergrowth, trees are felled at an angle of 45-60 degrees to the portage. Since it is difficult to take the entire half-apiary at once in one run, it is divided conditionally into strips 8 wide-10 m. The strips are developed sequentially: first at the drag, and then, when the whips are shot, the strips farthest from the drag are developed. Clearing trees of branches can begin only after the feller has moved at least 50 meters from the cleaning site. Branches are used to strengthen the drag. Skidding must also be carried out outside the dangerous fifty-meter felling zone. The felling of trees and the skidding of sticks by the tops is carried out from the near end of the apiary. When loading a load, the skidder may come off the drag.

In addition to the scheme for the development of cutting areas, a basic diagram for the development of apiaries is drawn with the application symbols locations of individual logging operations (Figure 4).

Figure 4 – Schematic diagram of apiary development tape

method in the absence of reliable viable teenagers

The diagram shows an apiary with a width of 40-45 m, in the middle of which a 5 m wide drag is laid. In this case, the drags are cut in advance. The cutting of the drag begins from its far end, the first trees are felled into the free spaces between standing trees.

Then the half-apiaries are cut into strips 5 wide-8 m, which adjoin the drag at an angle of 45-60 degrees. The cutting of half-apiaries begins from the far end. The feller fells trees on the apiary belt, starting from the drag. In one go, i.e. on one belt, as many trees should be felled as necessary to collect one pack with a tractor. Skidding is done by trees behind the butt. When developing an apiary using this method, the tractor does not leave the drag. After felling trees on one belt, they must be shot immediately, otherwise trees on the next belt cannot be felled. In order to avoid downtime, the feller moves to the neighboring half-apiary, maintaining safety distances, or a tree choker is included in the team.

The method is used when deep snow in winter and on soft soils– in summer.

Cleaning felling areas. With any type of felling in a cutting area, after skidding and removal of wood, unused cutting residues (tree tops, twigs, branches, etc.) remain, which are scattered throughout the entire area of ​​the cutting area. They are approximately 15-20 percent of the growing stock. This interferes with the growth of undergrowth, natural reforestation, and preparation of soil for forest crops, increases the fire danger in forests by 1.5-3.5 times, and provokes the appearance of pests and diseases. Therefore, simultaneously with the felling of the forest or after its completion, the clearing of the cutting area is carried out.

Logging residues can be used for fuel, production of technological chips, turpentine, vitamin and pine flour and other valuable products.

I. S. Melekhov proposed combining the entire variety of methods for cleaning cutting areas into 3 groups: fire, non-fire and combined (11).

Methods for clearing cutting areas are established differentially, taking into account the types of forest and forest growing conditions, the type of felling, the technology used for cutting operations, etc., and in accordance with the “Rules...”.

“Rules...” recommended placing logging residues on trails when developing cutting areas with narrow apiaries and in waterlogged conditions, felling trees towards the trail so that the main part of the crown is located on it, followed by cutting off the branches and laying them across the trail. Felling residues protect the roots of the remaining growing trees from damage by tractor wheels. This method is most appropriate to use in spruce plantations.

Burning of logging residues used mainly on sandy loam and sandy, as well as on well-drained loamy soils by placing logging residues in heaps up to 1 m high and up to 2 m in diameter, excluding fire damage to growing trees and undergrowth. It is advisable to carry out burning during the snowy period.

Collection of logging residues for rotting It is used mainly in damp and humid growing conditions with their placement in small piles or shafts up to 1 m high and up to 2 m wide between stumps in areas free from undergrowth no closer than 20 m to the forest wall.

Chopping and uniform spreading of logging residues used on dry sandy soils in pine and hardwood plantations. This helps retain moisture and enrich the soil with organic matter, protecting self-seeding from the sun. This method is also used when there is economically viable undergrowth in the cutting areas. valuable species. The crushed logging residues are scattered in areas free from undergrowth. For fire prevention purposes, crushed logging waste should not occupy more than 60 percent of the felling area.

Reforestation activities have the goal of accelerating the reforestation process, creating conditions for the emergence of seedlings or the preservation of undergrowth or young growth of economically valuable species at the stages of the main forest felling and subsequent reforestation.

In clear cuttings for final use, passive and active measures are used to promote the natural regeneration of the forest.

Passive measures include measures, the observance of which during logging is mandatory: (organizationally–technical elements of clear strip felling):

Width of cutting areas: up to 50 m in coniferous and hardwood, up to 100 m– in soft-leaved forests for group I and 100 m– for scaffolding Group II;

- the next cutting area is cut down only after a complete renewal of the previous one (the main requirement for the period of adjoining cutting areas);

- the choice of rational technological schemes for the development of cutting areas in the presence of undergrowth (methods of narrow apiaries, for lining trees, etc.), as well as the choice of methods for cleaning cutting areas, etc. Cutting areas with the presence of promising undergrowth are developed mainly in the autumn-winter period.

Among the active measures to promote natural regeneration during clear-cutting, the following are most often used:

ABOUT planting seed trees that are the best from a breeding point of viewin an amount of 15-25 pieces/ha or 4-5 seed groups per 1 hectare, 3-6 trees per group. Seeds high class quality is given by trees of I-II Kraft classes, with a compact, highly raised crown, occupying no more than 1/3 of the trunk height;

M mineralization of the soil surface is carried out in the seed year on fresh cuttings in the presence of sources of contamination or under the forest canopy 3-7 years before cutting. For these purposes, special tractor rippers are used on light sandy and sandy loam soils,skin peelersand cutters(Appendix P).

The cultivated area in clearings should be 30 percent, and under the forest canopy– 15-20 percent. Tillage is carried out from the second half of summer, and in mixed plantings with the participation of deciduous trees in the fall, after the leaves have completely fallen. Under the canopy of a pine forest, tillage is allowed in early spring.

In conditions of damp, excessively moist soils, microelevations are created. On heavy loamy soils with the likelihood of their becoming swamped, ridges and shafts are created using double-dump forest and swamp–bush plows. If there is an admixture of aspen in highly productive pine and spruce plantations, soil preparation is carried out after preliminary ringing of the aspen using chemicals. Banding is carried out 5-6 years before logging;

- caring for self-sowing and undergrowth of target tree species includes clearing them of debris from logging residues, cutting down trees of low-value deciduous species and severely damaged target trees. Damaged hardwood undergrowth« put on a stump» .

Projected measures to promote natural forest regeneration are listed in Table 2.

table 2 – List of measures to promote natural regeneration of forests in cleared areas

Quarter number, Section No.	Area, ha	Characteristic plot *	Bonitet	Forest type type of forest conditions	Events for promoting natural reforestation
Note:

Clear cuttings forest plantations

Clear cuttings arose later than selective cuttings.

IN ancient times clear cuttings were not used for timber harvesting, but mainly for clearing land for fields, which modern classification more consistent with other fellings.

It was not until the 19th century that clear-cutting developed as a forestry system. Clear cuttings were a more rational and complete form of forest management than the unregulated or weakly regulated forced selective and mine cuttings that were widespread in Russia at that time.

The use of clear cuttings made it possible to obtain large quantity wood per unit area and stably meet the growing needs of industry, Agriculture and the population in the business and firewood industries. After clear-cutting, not always, but more often than after forced-selective felling, favorable conditions are created for obtaining reliable natural regeneration. But, most importantly, they made it possible to remove false and other genetically unreliable trees.

Over the course of the 19th and 20th centuries, clear cuttings gradually became widespread in our country and became the main method of cutting mature plantations (according to the classification in force at that time - final felling). However, at first, along with clear cuttings themselves, the so-called conditional clear-cutting (CCF).

During these fellings in the cutting area intended for clear cutting, not the entire tree stand was cut down, and the least operationally valuable part of the trunks, which did not reach the established diameter, remained standing. The implementation of SRM was justified from a silvicultural point of view by the fact that during standing felling, young, promising trees that had not reached operational size were left for growing. This is more or less true in plantings of absolutely different ages. But SRM was also carried out in even-aged stands, where their consequences were similar to the consequences of forced selective logging. The part of the trees that remained standing consisted for the most part from stunted trees of classes 4 and 5 dew (according to Kraft).

Modern Rules USR timber harvesting is not provided. Some positive experiences from these fellings were transformed into long-term gradual fellings that have completely different rules of purpose. They will be discussed in detail in the next topic.

During the period of industrial growth of the USSR economy, in conditions of an ever-increasing need for wood, clear cuttings began to be carried out more and more widely. However, the poor development of the transport network in the forests hampered this process. Then they appeared solid concentrated cuttings TO timber resource base- a section of the forest fund in which mature and overmature plantings are compactly concentrated - a logging road was laid, often a narrow-gauge one Railway(UZD). Clear-cutting areas were concentrated along it. Logging sites could have big sizes– up to a kilometer or more. They joined one another and turned into one huge clearing. The road was built further, and logging continued.

Clear cuttings in general and concentrated cuttings in particular, in which its main component, the tree stand, is completely or almost completely removed from the plantation, have a significant impact Negative influence to the forest in which they are held. The climate of extensive clear-cutting approaches that of extensive open space. All forest conditions in the complex change.

Wind speed increases in clearing areas. Snow in winter is blown to the edges of the clearing and does not form a thick cover. The soil freezes deeper, and the snow melts quickly in the spring. As a result, phenomena known to you from the forestry course occur that have a detrimental effect on seedlings and young growth. This:

1. freezing of parts of plants uncovered by snow and useful forest entomofauna overwintering in the forest litter, under extreme conditions low temperatures air;

2. “squeezing” seedlings on damp, heavy soils;

3. damage by late spring frosts to plants that began to grow early on soil that was prematurely cleared of snow;

4. death of plants due to “physiological dryness” caused by the fact that the buds begin to grow, and when the root system is frozen, the tissues are not supplied with water, and the young growth dries out.

In clearings, the air temperature is higher than under the forest canopy in hot weather, and in cold weather- below. In clearings, especially small ones, the probability of late spring and early autumn frosts is much higher than under the forest canopy. Under the influence of heat, the process of mineralization of the forest floor intensifies, and under the influence of precipitation and wind, some compaction of the soil occurs.

The hydrological regime of the soil in cleared areas also undergoes significant changes. A cut down tree stand stops the transpiration of water, and in damp soils, in the absence of surface runoff, it accumulates, causing waterlogging of the soil. Swampy clearings are overgrown with marsh grasses and moisture-loving shrubs - willows, alders, transpiration resumes, the soil gradually becomes swampy, but this takes a long time. On dry soils with a low groundwater level, even greater drying out of the soil occurs, because the roots of trees stop, absorbing moisture, raising it from lower horizons to higher ones.

The living ground cover in the conditions of most types of clearings is quickly replaced by light-loving species with a developed high aboveground part, the projective cover increases, and the sodding of the soil increases.

All these changes create problems for the natural regeneration of logging. Moreover, the more extensive the deforestation, the greater the problem, as a rule. .

In several better conditions There are soft-leaved species that bear fruit abundantly every year and have significant potential for vegetative regeneration. It is they who quickly occupy clearings in most forest conditions, and a classic change of species occurs. However, in forest types on dry sandy soils, pine and larch in cleared areas regenerate quite well without changing species. In forest types of the sphagnum group, pine also does not give way to other species in clearing areas. It’s just that in these conditions, herbaceous plants and soft-leaved trees generally do not grow well.

Cleared areas are better suited than many other categories of land for artificial reforestation—the creation of forest crops. The development of clear cuttings certainly stimulated the development of silviculture. However, it is important to create crops immediately after cutting is completed, until the above-mentioned changes in forest conditions have fully occurred. In production forests, primarily in concentrated fellings, this was often not possible. In addition, crops created in cleared areas require numerous first agrotechnical and then silvicultural care. Carrying out care requires huge costs for the operation of equipment and manual labor. In case of untimely or lack of care, crops are drowned out; deprived of light, they grow poorly. In autumn, the grass growing along the edges of the furrows falls onto the furrows, and the crops, pressed by the grass to the ground, damp out and rot along with the grass. Even if all care is carried out on time, it is not a fact that the crops will be successful. There are frequent cases of them getting wet, “squeezed out” and dying from exposure to other unfavorable environmental conditions.

As a result of many years of practice of widespread use of clear concentrated cuttings in the forests of Russia, today we have huge areas of soft-leaved young stands and middle-aged plantations, even in indigenous coniferous forest types. A considerable area of ​​clearings has turned into wastelands, swamps and plantations formed by shrub species.

Therefore, clear cutting should be carried out with restrictions. First of all, the size of cutting areas needs to be limited.

Clear cuttings with limited widths of cutting areas – solidnarrow-cutting (SLR)– have also been carried out for a long time, and are an alternative to clear concentrated cuttings. Adverse changes natural environment in their clearings they are not so pronounced; natural regeneration is more successful. Today these fellings are the most common.

However, to minimize the adverse consequences of clear cuttings and improve the conditions for their natural regeneration, restrictions on the size of cutting areas alone are not enough. There are several more rules regulating the location of cutting areas, their location in the block and the procedure for joining each other. They are generally called organizational and technical elements cutting area

· Direction of cutting area – the location of the long side of the cutting area in relation to the cardinal points. Logging areas CPR on flat terrain and on slopes no more than 10 degrees. have the long side perpendicular to the direction of the prevailing winds, and cutting areas on slopes of greater steepness are located along the horizontal lines of the slope, perpendicular to the direction of the slope.

· Cutting direction – the direction in which each subsequent cutting area is located relative to the previous one. The direction of felling establishes the sequence of allotment of cutting areas SLR in areas whose dimensions exceed the permissible sizes of cutting areas. The direction of felling cutting areas is CPR on flat terrain and on slopes up to 10 degrees. is installed against the prevailing winds, and on slopes of greater steepness - from the foot of the slope to

top.

Rice. 36 The direction of felling and the direction of cutting areas in an area located on flat ground. A – direction of the prevailing winds (western); B – direction of cutting areas (from south to north or from north to south); B – cutting direction (from east to west); 1, 2, 3, 4, 5, 6, 7 – the sequence of withdrawal of cutting areas and their entry into felling.

The direction of cutting on flat terrain is designed to reduce wind speed in clearing areas, and on slopes to reduce the risk of soil erosion.

The direction of felling is established in the interests of natural regeneration of fellings. Seeds from the forest wall that has not yet been touched by felling will fly with the wind (or downhill), ending up primarily in felling

• The deadline for joining cutting areas is the time interval after which felling is carried out in a cutting area bordering on a previously cleared one.

The timing of the contiguity of cutting areas is also established in the interests of resumption of logging, and takes into account average term recurrence of seed years in various tree species of Siberia.

The period for contiguity of cutting areas is established on both the long and short sides of the cutting area, regardless of the method of reforestation of the felled area - natural or artificial. In order for logging to resume, a contiguity period of 2–5 years is established.

In logging areas with preliminary renewal, the period for contiguity of logging areas with CPR is set at 2 years.

· The year of felling is not included in the period of contiguity of cutting areas! Method of joining cutting areas - method of placing cutting areas different years relative to each other.

There are 4 ways to connect cutting areas:

1. Direct adjoining of cutting areas.

The next cutting area joins the previous one after a specified period of joining along the long side (Fig. 37).

Rice. 37 Direct connection of cutting areas with a connection period of 2 years.

The direct adjacency of cutting areas creates optimal conditions for their renewal naturally, but this method has one significant drawback. With a small permissible width of the cutting area, the felling of a large plot of area may take a fairly long time (in the proposed example, the plot will be completely cleared in only 16 years; if the adjoining period were large, for example, 5 years, then the cutting would drag on until 2037! ) Over such a period, a ripe tree stand may well lose its commercial qualities.

It is possible to reduce the period of cutting down large areas with a small permissible width of cutting areas

2. Screw junction of cutting areas.

The next cutting area is joined to the previous one the following year through a wide strip (cutting edge) equal in width to double or triple the permissible width of the cutting area. Within the boundaries of the cutting area, the cutting area enters the cutting area with direct adjacency (Fig. 38).

Rice. 38 Rocker connection of cutting areas with a connection period of 2 years.

As shown in the figure, the period for complete clearing of the plot is significantly reduced. In plantings that require even more urgent cutting down, it is used

3. Interstriated junction of cutting areas.

The next cutting area is joined to the previous one the following year through a strip equal to the maximum permissible width of the cutting area. The missing strips are cut down after the established deadlines for joining the cutting areas (Fig. 39).

The use of inter-strip junctions of cutting areas is not allowed unless necessary, since wind speed increases significantly, and tree stands that are not sufficiently resistant to windfall and windfall can be severely damaged by the wind. Dark coniferous plantations are especially susceptible to wind damage. Plantings of other species growing on shallow, swampy and other unstable soils are also at risk. Therefore, inter-strip joining of cutting areas is rarely used, mainly in plantations whose stands quickly lose marketability.

From the point of view of providing conditions for the natural resumption of fellings, inter-strip abutment is inferior to direct and en-route abutment.

Rice. 39 Interstriated junction of cutting areas with a junction period of 2 years.

4. Checkerboard junction of cutting areas.

The cutting areas, cut in the form of chessboard cells, are joined to each other by corners annually, the rest are joined after the adjoining period

The staggered juxtaposition of cutting areas makes it possible to somewhat reduce the harmful effects of wind on uncut cutting areas. More suitable for areas whose dimensions exceed the permissible dimensions of cutting areas not only in width, but also in length.

Adjacent plots designated for clear cutting, belonging to the same type of farm, having the same method of renewal and the same position, can be combined into enlarged sections.

Clear-cutting areas in enlarged areas are located as in one area, without taking into account the boundaries of the areas that make up the enlarged area (Fig. 40).

Rice. 40 Placement of clear-cutting areas in an enlarged division, consisting of divisions 16, 17 and 22.

· Number of cuts in a quarter.

Shows how many clearcut cutting areas, not bordering each other, subject to felling in one year, can be allocated in a forest quarter.

Clause 45 of the Wood Harvesting Rules establishes that with a cutting area width of up to 50 m, 4 cuts per year are allowed, with a cutting area width of 51 - 150 m, 3 cuts per year are allowed, with a cutting area width of 151 - 250 m, 2 cuts per year are allowed, with a larger width logging is allowed 1 cut per year.

When allocating clear-cutting areas, all parameters of the organizational and technical elements of the cutting areas must be observed simultaneously.

During CPR, all trees in the cutting area are subject to felling. The exceptions are:

1. Trees of relict and endemic species. The list of species prohibited for logging throughout Russia is given in paragraph 15 of the Rules for the release of standing timber in the forests of the Russian Federation, 1998 (read it in detail). In addition, on the basis of the same paragraph, trees of other valuable and rare breeds, according to lists approved by authorities state power subjects Russian Federation, including those listed in the Red Book of the Russian Federation and the red books of the constituent entities of the Russian Federation. On the territory of the Toguchin Forestry Technical School, for example, Siberian larch is classified as such species.

Literature and regulatory and technical documentation:

(clear-cutting), final felling, in which the entire tree stand in the cutting area is cut down in one go. Clear felling of forest stands in separate sections (cuttings) has been carried out since ancient times, with the advent of the so-called. shifting agriculture, in which forest areas were cleared woody vegetation for growing agricultural plants. However, the widespread use of clear-cutting is associated with the harvesting of wood for the production of charcoal, which was used in the mining industry. At the end of the 19th - beginning of the 20th centuries. Clear-cutting has become even more widespread due to the development of the pulp and paper industry. The increasing demand for wood in the first half of the 20th century, and then the intensive mechanization of logging operations, led not only to a sharp expansion in the volume of clear-cut timber harvesting, but also to an increase in the size of cutting areas to 200 hectares (concentrated felling), a reduction in the period of contiguity of cutting areas (up to 1- 2 years). It didn't match natural processes dynamics of the forest (in particular, the periodicity of seed years, etc.) and over time led to negative silvicultural and environmental consequences(disruption of reforestation processes, shallowing and disappearance of small rivers, etc.). Based on a generalization of historical experience in clear-cutting in Russia and abroad within the framework of common system For final fellings, a system of “clear cuttings” has been formed. It is divided into 2 subsystems - with preliminary or subsequent reforestation. The main goals of clear cuttings, common to all final fellings - timber harvesting and ensuring the regeneration of economically valuable tree species - have their own specifics: almost simultaneous timber harvesting of the entire forest stand and corresponding complete reforestation. Clear-cutting has clear advantages over other types of felling (primarily selective): comparative simplicity of execution, maximum concentration of harvested wood in accessible areas, minimal costs for the construction of logging roads, timber-loading points and timber storage warehouses, etc. The main regulatory regulation of clear-cutting felling is carried out according to types, identified taking into account the characteristics of the regeneration of forest-forming species (see Type of final felling, Intensity of final felling).
Fellings with preliminary renewal are divided into 2 types - with natural renewal and artificial restoration. Clear cuttings with preliminary natural regeneration are carried out in areas with tree stands, under the canopy of which there is valuable viable undergrowth that can adapt to dramatically changed conditions and form a young forest stand. These are usually areas of even-aged, predominantly low- and medium-density coniferous and hardwood forest stands with a density of 0.5 and below, and soft-leaved trees with a density of 0.6-0.7 and below. The vitality and prospects of a teenager decrease as his age increases. For the zone of coniferous-deciduous forests of the European part of the Russian Federation, the maximum age of spruce regrowth that remains viable and promising under the canopy usually does not exceed 40-50 years. However, with movement to the north, the viability of the undergrowth remains even at a fairly high age (spruce - up to 80 years or more in the northern taiga subzone). Clear cuttings with preliminary artificial reforestation are not widespread. They can be carried out, if necessary, more smoothly than with subsequent renewal, changing generations of the forest. This is possible in areas where there is no natural regeneration of target species under the canopy of a mature tree stand and it is difficult or impossible to ensure it with measures to promote natural regeneration. Clear cuttings followed by natural regeneration (typical clear cuttings) are carried out in groups of forest types, where in the absence of preliminary regeneration of the forest stand under the canopy with additional assistance measures (partial removal of litter, mineralization of the soil surface or its loosening, etc.) natural regeneration of the target species is ensured . Such fellings are usually effective in groups of forest types with poor, sandy, dry soils (lichen pine forests, lingonberry forests and similar types in different regions countries), as well as on waterlogged soils when their surface is mineralized and microelevations are created. Clear-cutting followed by artificial regeneration (typical clear-cutting) corresponds to the nature of even-aged stands of such groups of forest types, where there is no preliminary regeneration of the target species and it is very difficult to achieve it by measures to promote natural regeneration. These are indigenous complex pine and spruce forests, oak forests and other groups of forest types of various forest growth zones, where there is great competition for herbaceous vegetation and a high probability of regeneration of non-target, usually soft-leaved species, and also in the absence of sources of natural regeneration. According to the parameters of cutting areas, 3 types of felling are conventionally distinguished: narrow-cutting, medium-cutting, and wide-cutting. Because the Negative consequences clear cuttings generally increase with an increase in the area of ​​cutting areas; their maximum value should decrease with the deterioration of environmental and forest conditions. In the most optimal conditions for forests in the southern and middle taiga subzones of the European part of Russia, taking into account the characteristics of forest types, logging can be carried out with different normative and permissible parameters for cutting areas. With the increase in extreme ecological conditions for forests in the southern and northern directions, wide- and medium-forest clear-cutting is limited or excluded. Appropriate restrictions are necessary when environmental conditions become more complex within one forestry district or natural area, primarily for forest types with unstable, poor, shallow soils (lichen, etc.). Similar restrictions are necessary in mountain forests - in the direction from bottom to top, with increasing slope steepness, taking into account their exposure - from northern (north-eastern, northern, north-western) to southern (south-eastern, southern, south-western, western ). Significant differences in the consequences of clear cuttings are associated with the parameters and features of almost all organizational and technical elements of cutting areas. The width of cutting areas is of primary importance for typical clear cuttings with subsequent regeneration (especially natural) of coniferous and hardwood species. Due to the small radius of scattering of seeds (50-100 m) of these species, narrow cuttings followed by natural reforestation are most acceptable and effective in areas where forest walls are used as sources of seeding. In forest-forming coniferous species (pine, spruce, larch, etc.), forest walls can provide seed regeneration in cutting areas up to 100-150 m wide. In hardwood species with heavy seeds (oak, beech), only a small strip (slightly larger than the radius) is seeded from the walls crowns), which corresponds to the minimum width of the cutting area established for seed oak - 50 m. The width of the cutting area for Siberian pine pine can be set similarly. In addition, in a narrow cutting area, the forest walls provide quite favorable environmental conditions compared to treeless space. The weakening of the seeding function of forest walls with an increase in the width of the cutting area is to a certain extent compensated by leaving sources of seeding in the form of individual stable seed trees, seed groups, seed clumps and seed strips. Individual trees or small groups of 3-5 trees are left in lichen pine forests (10-15 trees per 1 ha) and lingonberry pine forests (15-20 trees per 1 ha); in pine forests of the blueberry group of forest types, groups of trees of 5-6 pieces are left. in the amount of 15-25 groups per 1 hectare. The distance between groups should not exceed 100 m, and to simplify the implementation of other measures to promote renewal and subsequent harvesting (after performing the seeding functions), it is advisable to arrange them in rows or in another convenient pattern. Forest walls or intra-cutting sources of contamination can perform the function of seeding if cutting coincides with the harvest year. Since harvest years for many target species are repeated, as a rule, after several years, the period of contiguity of cutting areas should be no less than the period of repetition of fairly good harvests of renewable species. It is taken into account that the recurrence periods of productive years fluctuate significantly and differ significantly across regions and forest zones. Minimum standard adjacency periods are established taking into account the specified factors. If for the southern and middle subzones of the European taiga the adjacency period for pine and larch is set at 5 years, and for spruce and fir - 4 years, then in the northern taiga subzone it is 8 years. Along with the width of the cutting areas and the timing of the abutment, an important factor determining the total period of felling of forest stands is the number of fellings - cutting areas in one year. The maximum permissible number of cuts is established per 1 km of the territory in the direction of felling. The number of cuts is established in such a way that between them there are strips that are multiples of the width of the cutting area, in exceptional cases equal to it, but not less than 150-200 m, taking into account the stability of the strips left. Depending on the width of the cutting area, the number of cuts should be: with a cutting area width of 50 m - 5; 51-100 - 4; 101-150 - 3; 151-250 - 2; 251-500 m - 1. Operational capabilities clear cuttings may be regulated in lowland forests on the territory of watersheds or other territorial entities.