DIT ARTIKEL WORDT OP DIT MOMENT NAAR HET NEDERLANDS VERTAALD
To learn more, please visit the responsible forest management section for this region.
Direction of Cutting and the Abutment Method
The direction of the logging site is usually is chosen by positioning the long side of the logging area in relation to the sides of the world. Most times, perpendicular to the direction of the cutting.
Due to complexity surrounding harvesting in Siberia the Abutment Method chosen for individual logging sites might vary, especially in hilly areas, where different sides of the hills receive different amount of sunlight, which result in different conditions, and therefore require different abutment and harvesting methods.
Because most of our Siberian timber comes from around river Angara, with rocky slopes going down to the River, the methods we use are mostly Group-gradual and Selective Logging. It is only when we explore the forests farther away from the River that clear-cutting method and Long-Gradual logging is used.
Long-Gradual Logging Method
This method is used in stands with a well-defined second generation, which is left to grow. Secondary logging is carried out after the second generation reaches the age of ripeness (in 30-40 years). An indispensable condition for its conduct is a sufficient number of trees of the younger generation (at least 400 units per 1 hectare).
In the dry pine forests of Eastern Siberia (Forest Group III) our foresters use suitable there long-gradual cutting, and they account carefully for cranberry-grass growing pine forests. There the logging methods are selected taking into account the peculiarities of regeneration and the formation of the young undergrowth under the canopy as well as after felling. For example, in a fir grove continuous cutting quickly covered with a thick grassy vegetation, to-heaven hampers germination of seeds of tree species and inhibits the growth of natural regeneration and forest crops; in the forests of the same type at a gradual felling ground cover changes to a lesser degree and forest renewal processes are successful.
This method is the one in which a forest stand is cut in one step in a specially designated area – logging site. Clear-cutting is used in forests of all groups. The usual age in most forests of the southern and middle taiga is 100-120 years for pine, 120-140 years for spruce. However, for the Siberian larch the age is between 200 and 250 years.
To implement the method, the subsequent reforestation is carried out where there is no growth of the main breed. The growth should not be less than 1,5 thousand / ha. If it is less, then logging is allowed. Reforestation is carried out in 3 ways:
- Natural overgrowth - for this purpose seed-trees 20 units/ ha or seed curtains (0.3-0.5 hectares), totalling 5 curtains;
- Sowing of the forest - sowing in mineralized areas 2 - 3 kg / ha of seeds (aeroseeding);
- Forest planting - seeds and seedlings, material consumption 3 - 5 thousand seeds, 2 - 2,5 thousand seedlings.
After clear-cutting logging in the pine grove the vegetation is extremely rapid, and pine complex goes on deciduous species change; in the heather and cowberry such a change does not occur, and when carrying out the cutting measures to facilitate successful natural resumption of renewed pine. The cedar green moss Sayan (Eastern Siberia) contributes to the gradual resumption of logging cedar pine, ferns difficult to it (increased growth of grass cover after 1 Hour logging). When choosing methods of harvesting our foresters take into account the possibility of harmful insects and diseases. So, in the pine forests around central Volga basin have little Shelterwood infestation, whereas population density of the soil after clearcuts it is 4-16 larvae per 1 m3.
The peculiarities of the climate dictate that close attention is paid to the age structure of the standing forests (stands). In uneven stands, which occupy large areas, the forests of Group II and III rooted in well-drained soils our foresters use gradual and selective logging techniques of high intensity. In forest of Group I, voluntary selective logging yields better results.
Because the area around Angara river is very mountainous, our foresters implement far reaching methodology and practice solutions aimed at securing and ensuring that all conditions for forest renewal are plenty and in force. In these forests closer attention is to water-conservation and soil-erosion aspects of harvesting timber. This peculiarity maintains our technologists working in close cooperation with Federal Forestry representatives directly on the frontier of our forests in rather harsh conditions. As a result here we implement only Selective and Group-Gradual Logging and Group-Gradual Logging.
Currently our foresters apply the voluntary-selective and different variations for gradual cutting, with their intensity smaller than in lowland forests. Clear-cutting in the mountain forests is only allowed in some district tries on flat and gently rolling slopes, and our foresters are proud to be one of the few deemed up to the task.
When choosing methods of harvesting our foresters have to take into account the steepness of the slope and exposure. On steep slopes (20-30°) south, exposure usually allows only voluntary-selective logging of low intensity. Usually soil on northern slopes compared to soil on the southern slopes is more fresh and rich. On the southern slopes of the amplitude of daily temperature fluctuations is much higher and the humidity is lower than in the northern, so young trees growing on the southern slopes are affected by adverse climatic factors best exemplified by extremely high and low temperatures.
Given the soil and climatic conditions on the northern slopes clear cutting can be used more often with and the intensity of the harvest is higher. This is all achieved with the objective of maintaining the factors motivating the ecosystem natural potential to recovery and renewal, and keeps it in balance.
An equally important role play soil and resistance of soil to erosion when selecting methods of harvesting. Resistance of soil to erosion depends greatly on the steepness of the slope and exposure, and the count of the intensity of rainfall, soil capacity, it granulo-metric composition and porosity, density of the grass cover, bushes, etc. The most stable and powerful is permeable soil, usually located on the gentle slopes. In some cases, after the clear-cutting in the mountainous there is often erosion (Transbaikalia), in others around Sayan and Angara, the erosion is less intense. A lot of the difference arises due to the different mineral composition of the mountains coupled with steeper slopes, it is therefore absolutely necessary to keep in view the catchment boundaries, uniformly over the entire area.
Our foresters can not allow clear-cutting (felling) in the whole catchment area. In multiwood mountainous districts forest area should be at least 50-60% of the total catchment area; at 40-50% strength and less forest cover, only selective and gradual felling are used.