为明确不同大小林窗式疏伐对南方红豆杉Taxus wallichina var. mairei生长形质的影响以及珍贵用材培育成效，测定福建省明溪林窗式疏伐后马尾松林中18个林窗样地(按林窗面积划分为3种类型，Ⅰ：50～100 m2、Ⅱ：100～150 m2、Ⅲ：150～200 m2)的12年生南方红豆杉的生长、干形和分枝等指标，分析林窗大小与生长、干形和分枝情况之间的关系。结果表明，林窗大小显著影响南方红豆杉树高、胸径、冠幅、杈干率、通直度、圆满度、尖削度、径高比、枝间距、最大侧枝直径等10个生长形质指标和综合评价值。林窗Ⅰ、Ⅱ类型显著促进南方红豆杉的树高、胸径、冠幅生长和综合评价值。在干形指标方面，林窗Ⅰ、Ⅱ类型显著降低最大侧枝直径；林窗Ⅰ类型显著抑制分杈率，提高圆满度；林窗Ⅱ类型显著减少尖削度，提高通直度和径高比。在分枝指标方面，林窗Ⅱ类型显著提高枝间距。采用主成分聚类分析方法，依据18个林窗样地的南方红豆杉生长及形质性状的综合得分进行系统聚类，确定在95%置信区间内，林窗式疏伐的林窗面积为105.31～153.21 m2，可显著促进南方红豆杉生长与改良干材品质。

In order to clarify the effects of different forest gap size thinning on growth and form quality of Taxus wallichina var. mairei and the cultivation of precious timbers, 18 gap sample plots were established in Pinus massoniana forest after gap thinning in Mingxi County, Fujian, China to measure the indices of growth, stem form and branching indexs of 12-year old T. wallichina var. mairei plantations. The 18 sample were classified in gap size as follows: ClassⅠ, Ⅱ, and Ⅲ, which had a gap size of 50—100 m2, 100—150 m2, and 150—200 m2, respectively. The relationship between the gap size and growth, stem form and branching were investigated. The 18 gap sample plots were cluster analyzed according to the comprehensive score of growth, stem form and branching traits by principal component cluster analysis method. Determined the optimal gap sample plots group, estimate the optimal group gap size general parameter, and accurate optimization of the gap size of the gap thinning. The results showed that gap size significantly affected 10 indices, i.e. height, DBH, crown width, forking rate, stem straightness, stem fullness, taperingness, diameter height ratio, interval between branches, max-branch base diameter and comprehensive evaluation value. ClassⅠand Ⅱ both significantly promoted the growth of height, DBH, crown width and comprehensive evaluation value, and on the indices of stem form, both significantly inhibited max-branch base diameter. ClassⅠsignificantly inhibited forking rate and improved stem fullness. Class Ⅱ significantly reduced taperingness, improved stem straightness and diameter height ratio, both significantly increased intervals between branches. ClassⅠand Ⅱ significantly improved the comprehensive evaluation score of precious timbers. The optimum gap thinning was 105.31—153.21 m2 for gap size with a 95% confidence interval, which can greatly accelerate tree growth of forest and improve lumber quality.