RU2639325C1 - Method of clear cutting in spruce forests - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: method includes clear cutting of mature and overmatured spruce stands on a cutting area. During the cutting, a stepped canopy from young plants is formed by leaving trees below the average diameter of the cutting area stand on the cutting area borders, in strips with a width of 10-12 m. The adjunction of a next cutting area is carried out by forming a wind-resistant edge.

EFFECT: reducing commercial timber losses from desiccation and windfall in a stand strip adjacent to the cutting area and subsequent reforestation after clear-cutting in spruce forests.

2 dwg, 2 tbl

Description

The invention relates to forestry and can be used when carrying out clear-cutting operations in spruce forests of the European part of the Russian Federation, the Urals and Siberia.

There is a method of clear-cutting in spruce forests, which involves cutting all the trees in the cutting area in one go (Timber harvesting rules, 2011 - (1)).

The disadvantage is that during clear-cutting operations in spruce forests, subsequent reforestation by the root species is not ensured, and such negative phenomena as windfall and drying out of trees in forest stands adjacent to felling are observed. This process extends to a depth of 20 m from the forest wall. At the same time, the proportion of shrunken trees reaches 95-100%, and the proportion of windfall is usually 45-50%. The primary objects of drying out the windfall are the largest trees with a significant mass of the assimilation apparatus and the crown as a whole. The main reason for the drying of spruce trees is the effect of direct solar radiation on tree trunks, causing the death of cambial cells, the rupture of thin roots when the trees sway by the wind. The reason for the windfall was the increase in wind in the open cutting area, the superficial root system and the large windage of the crowns of the spruce trees. The complexity of the subsequent reforestation with spruce is explained by the impossibility of plaque seed from the forest wall over the entire area of felling. The intensity of these negative phenomena increases with increasing width of the cutting area.

The abandonment of single and bio-group seedlings at clearings is problematic because of their low resistance to wind loads, as well as the difficulty of cleaning them after the accumulation of undergrowth and the formation of young animals. The reason for the wind and the drying out, both of the seeders and the trees adjacent to the felling, is explained by a sharp change in the growing conditions after removal of the stand and, above all, by the increase in wind at the felling.

In 1975, in the north of the Perm Territory, a heavy wind threw out 20 million m ^{3 of} wood on an area of 260 thousand ha (Rozhkov and Kozak, 1989). Massive windfalls were observed in the Middle Urals (Turkov, 1979) in 1799, 1859, 1892. Wind speeds reached 35-40 m / s (126-144 km / h). Slower winds (20-24 m / s or 72-86 km / h) in the Middle Urals are repeated every 5-10 years, also causing a wind and windbreak, mainly in dark coniferous forests.

The general scheme of the influence of the forest on the wind is as follows (Molchanov, 1961; Osnovy ..., 1964; Protopopov, 1975; Belov, 1976; Melekhov, 1980; Molchanov and Gubareva, 1980; Alekseev, 1982; and others): when the air mass approaches the planting (the edge of the forest) it bifurcates - part of the air stream, accelerating, rushes up to 1 km or more, the other part, continuing to move, penetrates the plantation. Bifurcation of air mass into two streams begins before planting at a distance of 60-100 m, and sometimes up to 10-12 height of stands (Belov, 1976). The stream that rushes into the forest 10-30 m before the forest wall begins to condense and lose speed, and in the forest already at a distance of 120-150 m it does not exceed 6-7% of the initial open space speed, and at a distance of up to 250 m insignificant.

The spruce element of the stand is particularly active in braking the wind speed in the forest. The rougher the canopy, the faster the wind speed drops. The canopy of the spruce forest is rougher in the upper part compared to pine plantations, so the wind speed decreases faster over the spruce forest. Outside the forest, in the windward side, at a distance of up to 10 heights of stands, air masses at low speeds sink to the ground, and their speed is restored again up to 100 times the height of stands (Lugansky, 2010).

A known method of natural regeneration of forests at felling after completion of felling operations using a wood harvesting machine (patent for invention of the Russian Federation No. 2294092, 2007), in which after clear cutting, using machine harvesting of wood, seed strips remain on felling. These strips are left across the felling, first on one side of the logging mustache, and then on the other side, 150 m from the first strip, and thus the entire cutting area is developed. The strips are left with a width equal to the average height of the stand. This method allows to improve forest growing conditions at the felling and contributes to the subsequent natural reforestation.

The disadvantage of developing cutting areas with seed strips left is that it cannot be used in spruce forests, since they are most susceptible to windfalls due to the surface root system and drying out due to sharp changes in lighting conditions. In addition, this method of leaving seed strips evenly throughout the cutting area leads to a loss of growth of wood, since ripe and mature trees, even if viability is maintained, reduce their growth in seed strips due to a sharp change in environmental conditions.

The technical result is a reduction in loss of marketable wood from drying out and windfall in the stand adjacent to the felling area and ensuring subsequent reforestation after clear-cutting in spruce forests.

The technical task is to change the direction and speed of the wind near the forest wall and reduce the wind load due to a smooth change in the height of the left trees and the formation of a stepped canopy.

In FIG. 1 shows a well-known logging site after felling, where pos. 1, the wall of the forest, pos. 2 the direction of the prevailing winds, in FIG. 2 shows the formation of a stepped canopy of a windproof edge.

The method of clear-cutting in spruce forests includes clear-cutting of ripe and mature spruce plantations in the cutting area, while at the same time, part of the young fine-sized trees in stripes 10-12 m wide (half-section) are left along the borders of the cutting area. In this case, the size of the trees to be left increases with distance from the skidding trail, reaching a maximum value (average height of the stand before cutting) at the border of the wind-resistant edge adjacent to the felling (Fig. 2, item 3). Thus, a stepped canopy of young growth is formed.

After adjoining the next cutting area, a tonometer strip 10-12 m wide is also left, which is designed to mitigate the harmful effects of wind and side lighting on protected areas of the forest.

As a result of leaving the indicated strips from young thin-sized trees on the clearings, a decrease in wind speed, even distribution of snow along the clearings, less freezing of the soil and subsequent seeding with spruce are ensured. After felling, the stored tonometer sharply increases its growth and seed production, which allows for cutting by seeds, and after the formation of spruce young growth on the felling, cut the left strips and obtain marketable wood. Cleaning the left lanes after the formation of the young growth is technologically not difficult, since in the middle of the lane it is possible to lay a skidder by felling trees from two sides of it.

In direct proportion to the illumination in the stands is the process of emergence and growth of self-seeding, and then the undergrowth. The best light conditions for dark coniferous (spruce, fir, cedar) - with a relative completeness of 0.6-0.7 (Chmar, 1977). According to A.A. Molchanova (1978), high light intensity contributes to the development of tree roots.

The level of productivity of plant generative organs in forest stands largely depends on the lighting conditions (along with, of course, other environmental factors). Per tree, the fruiting is higher, the less often the stand. According to S.N. Sannikova and S.S. Sannikova (1985) in the Pripyshminsky pine forest in a 175-year-old pine in the Urals, with a decrease in completeness from 1.3 to 0.5, fruiting increased 5 times.

The data of the test plots laid in the strip of the green-moss forest stand adjacent to the felling 300 m wide showed (Table 2) that the fall in the control variant was 83% by reserve, while when the strip of thin gauge 10 m mortality did not exceed 0.7% 4 years after logging.

Thus, the claimed invention allows to reduce the loss of marketable wood from drying out and windfall in the stand adjacent to felling and ensuring subsequent reforestation after clear-cutting in spruce forests.

Literature

1. Timber harvesting rules: approved. Order of the Federal Forestry Agency (Rosleskhoz) dated August 1, 2011 No. 337.

2. The method of natural regeneration of forests at felling after logging operations using machine harvesting of wood: US Pat. No. 1194092 Ros. Federation. No. 2005218328/12; declared 06/14/2005; publ. 02/27/2007. 3 sec

Claims (1)

The method of clear-cutting in spruce forests, including clear-cutting of ripe and mature spruce plantations in the cutting area, characterized in that when cutting, a stepped canopy of young growth is formed by leaving trees below the average diameter of the forest stand in strips 10-12 m wide, and the next cutting areas are produced with the formation of a windproof edge.

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