摘要
[目的]研究不同强度采伐下马尾松的生长动态,筛选适宜的采伐强度,为马尾松人工林近自然经营提供技术支撑。[方法]2007年10月在14年生马尾松人工林(保存密度1 100株·hm^(-2))内进行采伐试验,设置4个采伐强度,即保留密度分别为225、300、375、450株·hm^(-2),以不采伐为对照;其后,自2008年开始连续8 a,每2 a测定1次马尾松的胸径、树高、枝下高和冠面积等生长指标,并计算单株材积和林分蓄积量,应用方差分析和Duncan多重比较分析生长指标对不同采伐强度的动态响应。[结果]表明:采伐强度显著影响林分生长,其中,林分平均胸径、单株材积、冠面积的年均增长量随保留密度增大而减小,但均显著高于对照(P<0.05)。采伐后第1 3年,马尾松冠面积增长量显著高于采伐后期,胸径则在采伐后第3 5年最高,而不同采伐强度对林分树高生长影响不明显。保留密度显著影响林分枝下高和蓄积量的动态变化,其年均增长量随密度增大而递增。5个处理间林分蓄积年均增长量的差异随林龄的增大而逐渐缩小。[结论]马尾松人工林生长对不同强度采伐的动态响应以树冠最敏感,冠面积首先陡然增大,进而引起胸径的快速生长。树高和枝下高在采伐后年均增量变化相对平稳。4个采伐强度均显著促进单株材积生长,而仅保留密度为225株·hm^(-2)的采伐对林分蓄积增长量影响显著。综合比较林分的单株材积和林分蓄积连年增长量,建议在桂西南15年生马尾松人工林近自然经营中宜选择300株·hm^(-2)的保留密度进行采伐。
Growth dynamics of Pinus massoniana were studied under intensive thinning so as to screen out suitable thinning intensity and provide technical support for close-to-nature management of Masson pine plantations. [Method]A thinning trial was conducted in a 14-year-old Masson pine plantation with stand density of 1 100 trees per hectare in October, 2007. Four thinning treatments including 225, 300, 375 and 450 trees left per hectare and the control without thinning were arranged. Since 2008, growth performance such as diameter at breast height （DBH）, height, height of crown base and crown area were measured every two years, and wood volumes were calculated at the single tree and stand level. These data were analyzed through one-way variance analysis and Duncan multiple range tests to reveal dynamical responses of these index to all sorts of thinning intensities. [Result]Stand growth performance were significantly influenced by thinning intensity, mean annual increments of DBH, single tree volume, crown area decreases with increase of stand density of thinning treatments, but they were all significantly higher than those of the control （P〈0.05）. The crown area increments of Masson pine were the highest during year 1 to 3 after thinning, while increments of DBH were the highest during year 3 to 5. No obvious relationship was observed between tree height growth rate and thinning density. Increases of crown base height and stand volume were significantly affected by stand density, and they increased with increase of stand density, while the differences of stand volume decreased with increase of forest age. [Conclusion]In the present study, Masson pine＇s response of crown growth to intensive thinning was the most sensitive and rapid. The crown area increased sharply at first, then resulted in rapid growth of DBH, while tree height and crown base height increased a bit stably. Thinning with four intensities all remarkably influenced the growth of single tree volume, but only thinning with 225 trees left per he
出处
《林业科学研究》
CSCD
北大核心
2017年第2期335-341,共7页
Forest Research
基金
全国森林经营基础研究项目(169201531)
中国林业科学研究院热带林业实验中心主任基金(RL-2012-02)
关键词
马尾松
强度采伐
密度效应
生长动态
Pinus massoniana
intensive thinning
density effect
growth dynamics
