The age of the lower store trees for the formation of dark coniferous forests after cutting

Abstract

The study is devoted to solving the problem of restoring radical (conditionally radical) spruce forests after cutting of birch forest stands. The purpose is to establish the optimal age of dark coniferous trees growing in the lower story of secondary soft– leaved forest stands for the successful restoration of a cut down area and reduction of period before cutting final stand too. The criterion was a change in the radial growth of trees preserved after cutting. Wood samples from undergrowth and undersized trees aged from 10 to 90 years were taken. The most active positive reaction of spruce and fir trees to changes of the forest environment conditions at the age of 40-50 years was noted. With a sufficient number and good condition of dark coniferous trees this age is the most promising for the formation of dark coniferous forests. In relation to them the age for cedar comes later by 15-20 years and is 60-65 years. It was found that the growth rate of healthy spruce, fir and cedar trees in diameter before and the first years after cutting are closely related. During the stand growth this connection may weaken. After cutting an increase of radial growth in healthy trees is accompanied by a

significant increases their height growth unlike trees that have any deviations from the norm (high, sparse, oval or spherical crown). The radial growth and apical growth in the healthy trees accordingly are 2.6–3.6 and 3.5–6.1 higher than trees with deviations from the norm. As a result of the high damage of fir trees the stand composition should be regulated in the direction of increasing the participation of spruce and cedar trees. For a dark coniferous forests form and shortening the period before cutting the improvement cuttings for spruce, fir and cedar must be carried out at the initial stages of the birch secondary forests formation.