林下套种及坡位和弱光环境对南方红豆杉人工林早期生长及林分分化的影响1）

为高效栽培南方红豆杉人工林，采用方差分析、径阶分布拟合和林木分级等方法，在福建省明溪县进行林下套种及不同坡位和弱光环境的南方红豆杉人工林早期生长及林分分化研究。结果表明：林下套种模式的12年生南方红豆杉林分的胸径、树高、冠幅显著大于迹地更新造林，其胸径、树高、冠幅变异系数较小。10年生林下套种南方红豆杉林分生长有着显著的坡位效应，除下坡与中坡间冠幅无显著差异外，其它均有着显著性差异，3个生长性状生长量和变异系数从大到小依次为下坡、中坡、上坡。在相同林分密度条件下，马尾松林下弱光环境10年生南方红豆杉林分的胸径、树高、冠幅显著大于杉木林下，但马尾松林下弱光环境南方红豆杉的胸径、树高、冠幅变异系数较小。不同培育模式及林下套种时，不同坡位和弱光环境的南方红豆杉人工林径阶分布采用Weibull分布函数拟合，效果较好；林下套种模式及其不同坡位和弱光环境均呈倒J型分布，即其林分结构相对稳定，竞争较合理；而迹地更新造林的林分径阶呈单峰左偏山状分布，表明其处于竞争的自然稀疏后期。南方红豆杉林分林木分级显示，除迹地纯林造林和林下套种的上坡位出现Ⅴ级木外，其它尚未出现Ⅴ级木。因此，营建南方红豆杉人工林应该进行培育模式、坡位和弱光环境选择，其培育模式宜选择林下套种，并在林下套种时优先选择马尾松林下弱光环境和中下坡。

Effects of Intercropping Pattern,Different Slope and Weak Light on Early Growth and Structure Differentiation of Taxus wallichina var.mairei Plantation

In order to realize the efficient cultivation of Taxus wallichina var.mairei plantation, the early growth and structure differentiation of T.wallichina var.mairei plantation with intercropping pattern, different slope positions and weak light en-vironments were studied by using variance analysis, diameter distribution fitting and tree classification method in Mingxi of Fujian Province.The DBH, tree height, and crown width of 12-year T.chinensis var.mairei plantation of intercropping pat-tern was significantly greater than that of reforestation, and the variation coefficient of the DBH, tree height, and crown di-ameter were smaller.There were significant slope effects on the growth of 10-year T.wallichina var.mairei plantation of in-tercropping pattern.DBH, tree height, crown width were significant differences except for crown width of downhill slope and middle slope, and the growth and variation coefficient descending order was lower slope, middle slope, and upper slope.In the condition of the same stand densities, the DBH, tree height, crown width of 10-year T.wallichina var.mairei plantation under the stand of Pinus massoniana was significantly greater than that of Cunninghamia lanceolata weak light environments.DBH, tree height, and crown width variation coefficient under the stand of Pinus massoniana weak light en-vironments were much less.The model fitting diameter distribution of T.wallichina var.mairei.plantation for different cul-tivation modes, slope positions and weak light environments of intercropping pattern with cumulative distribution function of Weibull distribution were good.The diameter distribution for plantation with intercropping mode, different slope positions and weak light environments of intercropping pattern were the reverse“J” type which meant the stands had been undergo-ing stable stand structure and reasonable competition.However, the diameter distribution for plantation of reforestation mode took single hump with left avertence shape which indicated that the stands were in the late stage of natural thinning of competition period.The forest classification of T.wallichina var.mairei plantation with different cultivation patterns, slope positions and weak light environments of intercropping pattern showed that there was not V grade wood except for reforesta-tion mode and uphill of intercropping pattern.Thus, it is necessary to select cultivation mode, slope position and weak light environment for T.wallichina var.mairei plantation, T.wallichina var.mairei plantation cultivation should be planted with intercropping mode, and optimally chose under the stand of Pinus massoniana weak light environment and middle and downhill slope position with intercropping mode.