林窗大小对油松实生苗地上部分构型的影响

Effects of Forest Gap Size on the Aboveground Architecture of Pinus tabulaeformis Seedlings

以陕西黄龙山油松人工林间伐产生的不同大小林窗的油松实生苗为研究对象,采用典型抽样法选择3个类型林窗,在各类林窗中设置样地,调查分析林窗大小对油松实生苗枝系构型、叶片特征及其在主干上的垂直分布,探讨油松实生苗对不同大小林窗的适应及其构型构建效果。结果表明:不同大小林窗下的实生幼苗地上部分构型和生长均存在明显差异,其中:(1)林窗大小对实生苗的地径、苗高、冠长和树冠面积影响显著。(2)实生苗的逐步分枝率、枝间距随林窗面积增大而增大,总体分枝率随林窗增大而减小。(3)实生苗的叶长和叶宽随林窗的增大而减小,但其叶的长宽比、总叶面积和平均单株叶数随林窗面积增大而增大。(4)林下油松实生苗的针叶在中下部分布较多,而林窗实生苗的针叶在中上部分布较多。(5)在不同的林窗中,相同年份生长的轮生枝上针叶数量、相对总叶数均随林窗面积的增大而增大。研究认为,在油松人工林经营管理中,可采取适当强度的间伐来创造林窗,尤其是增加大林窗的数量,以促进油松实生苗的更新和为培育优质干材的油松林提供保障,改善人工油松林林分质量。

Typical sampling method was conducted to select typical forest gaps of different size,each typical forest gap contained 3repeats,and the Pinus tabulaeformis seedlings from different size gaps in artificial P.tabulaeformis plantation of Huanglong mountain in Shaanxi province were selected as the research objects.The research was aimed at surveying the effects of forest gap size on branch architecture,leaves characteristics and their vertical distribution,and exploring the adaptation and architecture of P.tabulaeformis seedlings to different size forest.The results showed significant differences in the aboveground architecture and growth of P.tabulaeformis seedlings in different size gaps.（1）Gap size was positively related to caliper,seedling height,crown length and crown area.（2）With the increase of forest gap size,the stepwise bifurcation and interval between branch,while the total bifurcation ratio was declined.（3）The gap size was contrary correlated with needle length and width,but with the increased with needle lengthwidth ratio,total needle area and average needle number.（4）The needles in CK were mostly distributed in below middle part of seedlings,whereas the seedlings in forest gap were mostly distributed in above middlepart of seedlings.（5）With the increase of forest gap size,the needle number and relative total needle number of whorled branch in same year increased.In order to promote the regeneration of P.tabulaeformis seedlings,cultivate high quality wood,and improve the stand quality,we should adopted appropriate thinning techniques in the future.