不同间伐强度对阔叶混交林生长及径级结构的影响

通过对辽东山区阔叶混交林进行抚育间伐试验,结果表明:适度的抚育间伐可促进阔叶混交林林木胸径和蓄积生长,林分平均胸径和蓄积生长率随着间伐强度的增加先升高后降低,其中弱度间伐区林分平均胸径生长率最大,中度间伐区林分蓄积量生长率最大。间伐效果表现在伐后最初几年,随着时间的推移,林分平均胸径和蓄积生长率逐渐降低,各间伐区差异逐渐变小。随着间伐强度和林龄的增加,峰值向大径级位置偏移,分布范围明显地向大径级扩展。由不同间伐强度林分径级分布范围看,伐后4~21a,经过间伐的林分,径级分布峰值比对照区提高1~2径级。与对照区相比,各间伐区林分自然径级最大值、极差和直径离散度均有所增加,总体上表现出随着间伐强度和林龄增加而加大的趋势。综合考虑,中度间伐最有利于提高林分生产力,改善林分直径结构。

Effects of Different Thinning Intensities on Growth and Diameter Structure of Broad-leaved Mixed Forest

Thinning experiments were conducted on broad-leaved mixed forest in eastern Liaoning mountain area.Result shows that moderate tending thinning can promote DBH & accumulation of broad-leaved mixed forest of eastern Liaoning mountainous area,and the average DBH & accumulative growth rate of forest increase with the increase of thinning intensity and the average DBH growth rate is the largest in the weakly irrigated area,and the growth rate of the forest is the largest.Result shows that the average DBH & the growth rate of the forest decrease gradually with the passage of time,and the difference of the cutting area gradually became smaller.With the increase of thinning intensity and age,the peak shift to the large diameter position,the distribution range significantly expand to large diameter.According to the distribution range of different thinning intensity forest,the peak value of diameter distribution is 1-2 diameters from 4 to 21 years after cutting.Compared with the control area,the maximum,the difference and the diameter dispersion of the natural diameter all increase,and generally showed a tendency to increase with the increase of thinning intensity and age.Considering that moderate thinning is the most beneficial to improve stand productivity and improve the diameter structure of stand.