初植密度、间伐对杉木林分优势高生长过程的影响

立地质量是决定林分生长和收获的主要因素之一,在用材林经营与管理中,立地质量定义为“生长在某一地位上既定树种或林分类型林木的生产潜力”。以往的研究表明:许多树种的材积生产潜力与树高的生长成正相关;在同龄林中,根据较大林木树高生长过程所反映的材积生产潜力与树高生长之间的关系,受林分密度和间伐的影响不大;许多重要的用材树种其高生长几乎不受林分密度的影响,因而,根据林分优势高评价立地质量的方法即地位指数法是目前评定人工林生产力(立地质量)的一种通用技术[1]。使用地位指数法的目的有两个:(1)预估指数年龄的林分高(地位指数);(2)确定林分整个生长过程期望遵从的树高生长模型,并由此导出林分其它因子在不同立地质量条件下的生长过程,从而估计林分的生产潜力。

Effect of Planting Density and Thinning on Dominant Height Growth Curve in Chinese Fir Plantation

Based on Schumacher′s dominant height growth equation,this paper studies the effects of planting density and thinning on dominant height growth in Chinese fir (Cunninghamia lanceolata) stands by analyzing the changes of the curve parameters.The results show that the curve parameters are significant different among different stand density while there is no significant difference among different thinning intensity,so dominant height growth curves are much affected by stand density and little by thinning intensity.