Оптимизация режима прореживаний и проходных рубок в пойменных черноольшанниках

Abstract

In the steppe zone of Russia there is a tendency of increasing the proportion of mixed stands in the structure of riparian black alder forests. In middle-aged and maturing stands they occupy 21-23 % of the area. For such plants regulations of forming mode are absent, and for planting in pure content - require adjustments. In order to justify the feasibility and optimal standards of thinning in pure and mixed stands of natural and artificial origin thinning and felling were hold with a range of cutting intensity from very mild to severe. In pure stands thinning with intensity of 18 % has positively impacted: after 20 years, the average diameter, the absolute completeness and stock is higher for 14 %, 12.5 % and 14 %, respectively. Moderately strong felling in forest plantations of mixed composition had a negative result: in 17 years the completeness and the stock are 68.5 % and 68.4 % from control section indicators. According to forecasts, recovery of indicators of control stands does not happen in 30 years. After the thinnings in pure stands plantations, where grassroots method was used, had a better taxation structure: after 20 years after felling stock of experimental section exceeds the benchmark by 10.3 %, the completeness of- 10.2 %. The result of applying the method of crown thinning is deterioration in the structure of plantations: completeness and the stock reached the targets at 83.1 and 80.0 %, respectively. Thinning in mixed stands on condition of targeted reduction of the share of related species have a positive effect both on the dynamics of restoration of forest indicators and the improvement of sanitary structure of planting. An analysis of the results revealed the most effective cutting modes of formation and proposed regulations for modes of thinning in plantations of black alder of floodplain ecotype in the steppe zone of Russia.