Silvicultural Efficiency of the Thinning Efficiency of Pinus sylvestris L. Plantation in the Dry Subzone of Northern Kazakhstan Steppes

Abstract

Aim of study:Thinning efficiency after 18 years of cuttingat theScots pine (Pinus sylvestrisL.)plantations,in the subzone of the dry grass steppe,were examined.Area of study:On 45-year-old Scots pine plantations on the territory of the state enterprise "ZhasylAimak"in Nur-Sultan cityin the Northern Kazakhstan.Material and methods:The plantations were established by high density planting (13,300 seedlings/ha) of 2-year old seedlings. The planting was carried out on forest-suitable soils. To assess the silvicultural efficiency of the thinning in the plantation, the coefficient of growth tension or a complex estimated figure (CEF)was used.Main results:The research confirm that Scots pine plantations can be establishedin the subzone of dry fescue feather-grass steppe(Festucavalesiaca-Stipetum capillataeSillinger 1930). The maximum silvicultural effect of thinning was achieved with three steps. Inthe 1ststep of the thinning of the forest,10-15 yearsoldtrees are cut down. Trees with over-developed crown are also cut down. The 2ndstep is made in 25-30 years with thinning intensity of 25% by stock. The 3rdstep is made in 40-50 years in a uniform way.Highlights:In the harsh climatic conditions of Northern Kazakhstansteppe, deciduous trees and shrubs begin to age and die much earlier than the long-lived Scots pine.