不同间伐梯度下云南松幼林林分结构及林木生长变化

Stand Structure and Tree Growth of Young Growth of Pinus yunnanensis under Different Thinning Intensities

2012年分别设置10%、20%和30%抚育间伐梯度和对照（不间伐）对昆明西山林场2001年过火地段上自然更新的云南松（Pinus yunnanensis）幼林进行抚育间伐,分析林分结构变化及林木生长情况。2012年和2014年结果表明：样地平均林分密度差异不大,在10 500~12 500株/hm2,除对照样地出现林分密度增加,这是由于随着林木生长,部分林木进入起测径阶,从而增加了林分密度值。通过采取不同抚育间伐强度措施后,林分平均高变化以对照和30%间伐强度为高,接近20%,而10%和20%两个间伐梯度增长仅略高于10%;林分优势高的变化则在三个梯度及对照之间变化不大,均增加16%以上,最高仅20.00%;而林分平均胸径变化差异较大,对照的仅增长10.96%,而30%的抚育间伐梯度下则增加41.77%,10%和20%两个梯度增加在30%左右;三种抚育强度下直径生长均显著高于对照,但10%和20%两个梯度下差异不显著。因此,抚育间伐管理对于林分高生长影响不大,而对林分直径生长起到较大的提升作用。

Experiments were conducted in 2012 at young growth of Pinus yunnanensis of burned-over area in 2001 in Xishan Forest Farm of Kunming, Yunnan province, with different thinning intensities（10%, 20% and 30%）. Investigation in 2014 demonstrated that mean tree height growth increased by 20% at sample plot with 30% thinning and control（no thinning）, while 10% at that with 10% and 20% thinning plots. Height growth of dominants had no great difference among different treatments and control, but mean DBH increment had significant difference, 10.96% at control, 41.77 at sample plot with 30% thinning, about 30% at sample plots with 20% and 10% thinning. The experiments indicated that different thinning treatments had no evident effect on tree height growth, but could improve diameter growth.