The tendencies in the condition of field-protecting shelter belts in southern Siberia

It is proposed to analyze the stands’ condition to use the method of tendencies, which occupies an intermediate position between a static evaluation of the life conditions and the dynamic assessment of the condition. The trends take into account the totality of the factors, affecting the condition of the trees. The basis for the method is the analysis of tree distribution by the categories of condition. This approach allowed us to identify a set of factors affecting the condition of the trees, depending on the growth conditions of soil and tree species. Siberian larch is characterized by healthy condition, regardless of the method of planting, density, number of rows and soil conditions. This situation can be explained by shelterbelts’ age not exceeding 20 years. At older ages, the soil conditions influence field-protecting forest belts. The best conditions are formed in the stands on the southern chernozems of pure composition, with a row and chess-type of planting. In clean multi-row pine stands, the trees are more healthy condition, compared to mixed stands. The living condition of birch stands is weakened. Favorable conditions found in pure Siberian elm stands with a 3-row and chess-type planting, compared to mixed stands. Relatively favorable conditions for the growth of black poplar trees were observed in pure 4-row stands, growing on ordinary chernozems. Point scale assessment of the stands shows that healthy state have larch belts in the steppe of Shira lake. Field-protecting shelter belts in the Republics of Khakassia and Tyva, with some exceptions, are in weakened and badly weakened condition. In those stands conducting agronomic and silvicultural treatments to improve mineral nutrition and moisture supply is the urgent need