抚育间伐对云南松中幼林的影响

Effect of Thinning on Mid-young Pinus Yunnanensis Plantations

云南松是云南省主要的用材树种之一,但长期以来经营水平低下,造成林分结构不合理,林分密度偏大,林木竞争激烈,生长势差,影响林分质量和产量。为了解抚育间伐对云南松中幼林生长的影响,通过连续5a对云南松中幼林的11块抚育间伐监测样地和4块未抚育间伐对照样地的胸径生长和树高生长进行对比分析,结果表明,抚育过的林分的平均胸径总生长量为5.21 cm,与未抚育的相比差异显著,且随时间变化增幅和增速不断增大,但抚育措施对树高无明显影响;抚育后的林分的单株材积年均生长量和五年内总生长量与未抚育的相比分别提高100%和60%,总体上抚育间伐对云南松中幼林单木材积有显著促进作用,对样地蓄积和公顷蓄积无显著影响;抚育后,年份因子与林木胸径(F=29.049,p<0.001)、单株林木蓄积(F=29.049,p<0.001)和样地蓄积(F=29.049,p<0.001)关系显著。

Pinus Yunnanensis is one of the main timber species in Yunnan province. Stand quality and productivity are signifi-cantly influenced by the unreasonable stand structure, relative large density, trees competition and poor growth potential. Through 5 years investigation of tree diameter of breast height（DBH）and the height growth between 11 thinning and 4 untouched patches, it was showed that the total increment of tree DBH was 5. 21 cm after thinning, which was significantly higher than that of untouched patches; the increasing range and speed would increase in follow time, but thinning measures had no significantly effect on tree height. The to-tal annual individual volume increment and the total increment in five years with thinning increased 100% and 60% respectively than that untouched. On the whole, the thinning significantly increased the individual tree volume of young and middle aged Pinus Yun-nanensis 9 but had no effect on plantations and hectare volumes. The tending years is key factor which significantly connected with trees DBH（F = 29. 049, P 〈0. 001） , individual tree volume（ F = 29. 049, P 〈 0 . 001） and plantations volume（ F = 29. 049, P 〈 0. 001） after thinning.