In the complex of environment-specific functions of the Carpathian mountain forests, their soil protection properties are very important. However, in quantitative terms, the information about it in the literature is not abundant. Complex relief and storm activity cause here frequent erosion, collapse-osseous and landslide processes, in connection with which the soil protection role of the forests is quite significant. It is actualized by a total application in local high-yield mixed and pure spruce stands of whole-limed shafts with tractor trapping of wood, which often intensifies peculiar to the area harmful phenomena.
The aim of the study is the quantitative assessment of the soil protective role of Gorgan's forests depending on the features of mountain relief and logging activities.
Materials and methods
To determine the anti-erosion functions of forests and their territorial variations, a complex of the following issues was studied:
- Influence of forest cover of mountain catchments on prevention of ground and solid river sediments ablation;
- Reduction of the processes destructing coasts of the hydrographic network in forest conditions compared with the field ones;
- Distribution of stone fields and their localization with forest vegetation;
- Preservation of soil cover during forest exploitation on skidding tracks during continuous and selective felling.
The solid river sediments served as the main indicator of the processes of soil ablation and erosion. Now it is proved in the numerous literature sources that the volume of erosion and solid runoff depend on atmospheric precipitation, slope steepness, altitude, vegetation, farming practices and on a number of other, less significant, factors.
Against the background of complicated geomorphological conditions of the Gorgan mountain range, its forests fulfill important soil protection properties. The present forest cover of 78 % provides reducing erosion processes by 4.3 times. At the same time, in the upper part of the mountain slopes, the protective role of the forest is twice as high as in the low mountains. In the forest-covered areas, the scale of coastal destruction by flood waters is 1.5–2.2 times smaller than that of open areas.
In the rocky deposits of Gorgan, whose area is increasing with high altitude, important protective and soil-forming functions belong to high-altitude fir-spruce forests, which localize the placers and prevent collapse-osseous processes.
During forest exploitation operations, the soil-preserving effectiveness of the selective felling is 2.3 times higher than of the continuous ones. At the same time, it is important to minimize the network of skidding tracks.
In order to preserve and enhance the soil protective properties of Gorgan forests, it is necessary to create anti-erosion and shore-fixing forest belts, to promote forest-bearing processes on rocky margins, to give preference to a selective system of forestry management in a continuous manner, and, in particular, to regulate the network of skidding tracks on forest felling taking into account the steepness of the slopes. In areas vulnerable to erosion, the system of forest management activities should be strengthened by hydroengineering methods of protection against the elements.
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