杉木中密度幼林光环境与生长修枝效应

Effect of pruning on stands light environment and growth of middle-density Chinese fir young plantations

采用LAI-2000冠层分析仪对不同修枝高度处理条件下杉木人工幼林光环境及叶面积指数的动态变化进行了分析,并探讨了生长量的修枝效应,初步得到4点主要结论:(1)修枝明显提高了林内透光率,林内透光率随着修枝强度的增大而增大,且修枝强度愈大,林内透光率恢复至干扰前状态的趋势愈明显;(2)修枝明显降低了林分叶面积指数,随着修枝强度的增大,林分叶面积指数呈线性下降,修枝强度高的林分叶面积指数的增长百分率相对愈高,修枝所引起的林分叶面积指数下降的程度远远低于林分透光率的增大;(3)不同修枝强度对隔行修枝林分的总生长量影响不显著,但过度修枝会对修枝木胸径生长产生抑制,而对修枝木高生长影响不显著;(4)强度为40%的修枝方式以约20%的叶面积损耗换取了透光率1倍左右的提高,且对修枝木材积生长影响不显著。

The dynamics of light environment and leaf area index （LAI） of Chinese fir young plantations under the condition of different pruning height treatment were studied using canopy analyzer LAI-2000, and the effects of pruning on stands growth were discussed. Four main conclusions were gotten. （ 1 ） Pruning obviously improved stands light transmission rate, the canopy light transmission rate increased with the increasing of pruning intensity, and the bigger the pruning intensity was, the more obvious the restoration trendency of canopy light transmission rate was with the stands growth. （2） Pruning obviously decreased LAI, LAI presented a linear descent with the increasing of pruning intensity, the increasing percent of LAI was higher for stands with high pruning intensity than ones with low pruning intensity, and the effect degree of pruning on LAI was far lower than on canopy light transmission rate. （3）Pruning intensities had not produced significant effect on gross growth for every other one row pruning treatment, the excessive pruning could significantly decrease the breast-height diameter of the pruning trees, but had not significant effect on height. （4） Only with the 20% leaf area loss, the 40% pruning intensity could make canopy light transmission rate increase one times or so, and this pruning intensity hadn＇t significant effect on timber volume of the pruning trees.