单 位：
东北林业大学;黑龙江省林业厅“三北”防护林指导站
关键词：
白桦(Betula platyphylla Suk.);天然林;抚育间伐强度;修枝强度
摘 要：
1998年 ,对林龄为 2 0～ 30a的白桦天然林进行了不同强度的修枝和间伐处理 ,并于 2 0 0 3年春对林分生长状况进行了复查 ,结果表明 :不同强度的间伐和修枝处理对白桦天然林林木胸径生长和冠幅具有显著影响。强度修枝 (2 /3树高 )后 ,林木的胸径生长比弱度修枝降低 8%～ 10 %。中度间伐和强度间伐对保留木胸径生长和冠幅影响较为接近 ,但显著高于弱度间伐。树干解析结果表明 :间伐后 ,林分的材积生长量以中度间伐为最大 (6 .99m3 ·hm-2 ·a-1) ,强度间伐最小 (4.6 1m3 ·hm-2 ·a-1)。 5a的研究结果表明 ,林龄 2 0～ 30a的白桦天然林最适林分密度为 110 0株·hm-2 ,修枝强度不应超过 1/2树高。
译 名：
Effects of Thinning and Pruning on the Growth of White Birch in Natural Forests
作 者：
Sun Zhihu, Wang Qingcheng(Northeast Forestry University, Harbin 150040, P. R. China); Liang Shujuan(“Three Norths”Protective Forest Construction Office of Heilongjiang Province)
关键词：
Betula platyphylla Suk.; Natural forest; Thinning intensity; Pruning intensity
摘 要：
Different intensities of thinning and pruning in 20～30-year-old natural birch stands were conducted in 1998, and stand features were surveyed to 60 permanent plots. The resurvey in 2003 shows that the effects of different thinning and pruning intensities on DBH increment and crown increment of white birch trees in natural forests are significant. A decrease of 8%～10% of DBH increment has been found in high intensity pruning treatment (2/3H) in comparison to that of low intensity one. The intermediate and high intensity thinning treatment produce similar DBH and crown increments which are greater than those in low intensity thinning treatment. Result from stem analysis of trees under different thinning treatments indicates that the stands treated with intermediate thinning intensity give the highest stand volume increment(6.99 m 3· hm -2 ·a -1 ), while those treated with high thinning intensity show the lowest volume increment (4.61 m 3· hm -2 ·a -1 ). The 5-year study indicates that the optimal thinning treatment for 20～30-year-old natural birch stands is to maintain a stand density of 1 100 stems· hm -2 and the pruning intensity should not exceed 1/2 tree height.
