The influence of density on the biological stability of recreational pine forests of the SNPP “Bayanaul”

The data presented of effect of stand density on the state and biological stability of recreational pine forests of Kazakh Upland (for example, the State National Nature Park (SNPP) «Bayanaul». Object of research are natural and artificial pine forests II and IV age class, which grow in dry (forest type C2) and fresh (forest type C3) forest-growing conditions. The studies found that in high-density pine stands index of vital status (IVS) and index of relative live status (Ln) varies from 63.0 to 71.0%, which give grounds to rate them as «weakened» or biologically non-sustainable. The greatest value of index of vital status (IVS) and index of relative live status (Ln), equal to 75.7 and 85.9%, characterized medium-density pine forest stands, state of which is assessed as “healthy”. The main share of trees and their stocks in high-density pine forests on the category of the state of “weakened” - up to 60-70%. In medium-density pine forests main share of trees and their stocks are the “healthy” trees - up to 55-70%. The number of “greatly weakened” and “dying” trees in the high-density forest is 11-26%, in medium-density pine forests their number in 1.5-3 times less. Share of stock of trees in category of vital status “greatly weakened” and “dying” does not exceed 9%. The largest part of the stock of «healthy» trees in the pine forests fall on the larger stage thickness (16-24 cm) - up to 75%. The main part of the stock of trees belonging to the category of state “greatly weakened” and “dying” on most study plots, falls on the small stage of the thickness (8-12 cm) - up to 80-100%. In high-density stands established a relationship between vital status and size of trees that can be approximated by polynomial function. In medium-density stands correlation of these indicators are not sufficiently expressed (R2=0,632). Regulation density of recreational pine forests of SNNP «Bayanaul», by removing “greatly weakened” and “dying” trees will not only control the process of the oppressed mortality and slower growth of trees, thus improving the biological and fire resistance of forest stands, as well as increased their recreational attractiveness.