Growth dynamics of forest - forming species in field - protective forest strips in the south of Western Siberia

Introduction. Creation of systems of interacting forest belts is a prerequisite for farming safety in the south of Western Siberia. For their design it is necessary to know the height, wind permeability and functional longevity of stands of established plantations. The aim of the study is to determine the growth characteristics of the main forest - forming species in different soil and climatic conditions of the region. Materials and methods. The studies were conducted on temporary sample plots using standard techniques of growing forest taxation, analysis of growth progress of model trees and mathematical data processing. Results and discussion. It has been established that on chestnut soil stands of 2-4-row FPFS up to 20-25 years old have predominantly healthy appearance, openwork windbreak profile, which are little conditioned by groundwater availability, planting density and placement of planting sites. Elm and pine form the densest rows. Forest strips of these species are less differentiated in condition, structure, and growth energy and compare favorably with birch and, to a lesser extent, larch plantations, which on dry habitats begin to thin out early, lighten and hinder the expansion of steppe grasses. After 25-30 years, differences in the condition of forest belts rapidly increase. In dry conditions, a reduction in the number of rows and widening of row spacing has a positive effect on stand growth. Moderately dense (0.6-2 thousand sods/ha) stands of relatively shade - tolerant species grow and persist longer. In lowlands and southern black soil, on the contrary, closed stands of all species, regardless of forest - cultural differences, continue to grow steadily and fulfill the field protection function even at the age of 40-55 years. Conclusion. In the dry and arid steppe of Western Siberia, differences in the growth and condition of middle - aged stands of low - row forest belts are mainly determined by their density and soil moisture supply. On southern black soil and on chestnut soil differences of depressions moderately dense forest belts are 4-6 m higher and retain viability for 20-30 years longer than on auto - amorphous chestnut soil with inaccessible groundwater horizon. The 2-row strips are somewhat higher, while 3-4-row strips are lower. Less light - loving species (pine and elm) live longer in dry conditions. Birch and poplar grow faster in lowlands and on southern black soil. However, in 4-5 decades they are inferior to pine and larch in terms of plantation condition. The advantage goes to closed but relatively rare 2-row coniferous forest belts. Suggestions for practical application and direction of future research. The results of research can be used in the design of reconstruction of existing and creation of new systems of forest strips in Altai Krai and Novosibirsk Oblast, as well as in other regions of dry - steppe and arid - steppe zones, on fields subject to deflation and water erosion. The actual direction of research development is the development of effective forest - cultural methods of plantation formation.

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