Сибирский лесной журнал (Jun 2020)
Assessment of potential productivity of tree stands based on forest planning materials (on the example of «Azas» state natural reserve)
Abstract
On the example of the Azas State Natural Reserve, the potential productivity of forest stands is considered depending on the indicators of forest growth conditions. Multiple regression equations are formed. The class of productivity (bonitet) is used as a function. Initial information for drawing up the equations - materials of forest planning and data of digital elevation model. Soil, moisture and heat are the main factors affecting the development of the stands. The heat supply of locations is considered as a derivative of relief parameters. Soil moisture and fertility indicators of locations are constructed based on the characteristics of forest inventory indicators. The Siberian larch and the Siberian stone pine forests are found throughout almost the entire high-altitude profile of forests in the reserve: the range of absolute heights of larch about 1600 m, the Siberian stone pine – 2200 m, Scotch pine – 700 m, the Siberian spruce – 500 m. It turns out that the vertical temperature gradient significantly affects the representation of tree species in the high-altitude zones of the reserve, but practically does not affect the productivity of the stands. A significant decrease in the class of bonitet as the climb is observed only in larch stands. The effect of slope on productivity is not observed. The ranked number of soil moisture is demonstrated relative to the generalized qualitative indicator of forest-growing conditions of the forest type. There is a statistically significant relationship between the index of forest growth conditions and soil types. It is revealed that the class of bonitet of Scotch pine stands is determined mainly by soil moisture; in larch stands there is a dependence of the class of bonitet on the absolute height of the terrain, humidity and soil fertility; the productivity of the Siberian stone pine and the Siberian spruce stands naturally depends on soil moisture and fertility. Mapping of the potential productivity of stands is made by the values of the absolute height, soil moisture, and soil fertility of forest inventory compartments. Visual analysis of the map shows: on the best mode of moisture and soil fertility, located on the heated areas, can potentially grow more productive stands; it is established that within the reserve the most favorable forest conditions have developed on the terraces of the Azas river, meadows, forest-steppe areas; as elevation increases, forest conditions deteriorate.
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