马尾松天然次生林密度调控生长时效性的初步研究

Study on temporal effectiveness of the growth regulated by density of natural forest of Masson's pine

对马尾松天然林进行不同密度调控试验 ,在林分改造 12a后生长结果表明 :(1)间伐后不同的保留密度对树冠发育 ,胸径、单株材积、林分蓄积的生长影响显著 ,其随着保留密度的增加 ,各生长指标逐渐减小 ,这说明间伐前期对马尾松胸径的影响效应可保留相当长的时间。但从生长时效性看 ,间伐后密度对林分胸径生长的影响主要在间伐后的 1～ 3a内 ,此后每年的胸径增长效应逐渐减弱。 (2 )间伐后保留密度的不同 ,对林分树高逐年生长没有明显的规律性 ,但对其枝下高有一定影响 ,随保留密度减小 。

The natural forests of Massons pine were thinned and there remained five sorts of planting density of 1 190,1 510, 2 140, 2 330 and 2 860 per hm 2 The results in the twelfth year post thinning showed that the effects of remained density on DBH and tree volume were significant,also on branch height and stand volumes.As the densities increased,the growth reduced,with little effect on tree height.The current annual increments of DBH and height suggested that the effect of density remained on DBH mainly concentrate in the period of 1～3 years after thinning then the each years effect be gradually reduced,however,the early effect can remain a long period,and on regularity of the current annual increment of tree height be found.