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 cutting at the Scots pine (Pinus sylvestris L.) 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 city in 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 established in the subzone of dry fescue feather-grass steppe (Festuca valesiaca-Stipetum capillatae Sillinger 1930). The maximum silvicultural effect of thinning was achieved with three steps. In the 1st step of the thinning of the forest, 1015 years old trees are cut down. Trees with over-developed crown are also cut down. The 2nd step is made in 25-30 years with thinning intensity of 25% by stock. The 3rd step is made in 40-50 years in a uniform way. Highlights: In the harsh climatic conditions of Northern Kazakhstan steppe, deciduous trees and shrubs begin to age and die much earlier than the long-lived Scots pine.