华北山石区落叶松混交林空间结构研究

Study on the Space Structure of Mixed Forest of Larix principis-rupprechtii in the Mountain Area of North China

为指导落叶松混交林抚育经营,对华北山石区落叶松混交林林分组成和空间分布格局进行研究。结果表明:样地A的总密度和总断面积均最小,为1 007株·hm^(-2)和24.446 4 m2·hm^(-2),样地C最大,为1 525株·hm^(-2)和47.280 2m2·hm^(-2),样地B居中;华北落叶松在样地A中胸径最大为18.6cm,样地B最小为18.1cm,而树高则相反。样地A的平均角尺度为0.358 8,均匀分布,林分处于较为稳定的状态,林分中落叶松为均匀分布状态;样地B平均角尺度为0.523 8,为团状分布,林分中落叶松为均匀分布;样地C的角尺度为0.508 5,为随机分布,林分中落叶松为均匀分布,云杉处于团状分布状态,五角枫和花楸处于随机分布状态。样地A直径大小比数的平均值为0.333 1,林分中落叶松和白桦的大小比数相差不大,表明林分空间分化程度比较小,两种树种的优势度相差无几;样地B的大小比数为0.487 2,林分中落叶松处于优势,而蒙古栎、山杨、五角枫和花楸处于劣势,其它树种处于中庸状态,而且各树种的大小比数有一定的差别;样地C的大小比数为0.484 5,云杉和华北落叶松处于绝对优势;样地A混交度为0.47,属于重度混交;样地B混交度为0.37,混交程度比较低下;而样地C混交度为0.83,说明杉落针阔混交林树种组成较多样化,结构更加稳定,在空间利用上也更加充分。

In order to guide management of larch mixed forest, the stand composition and spatial distribution pattern of larch mixed forest of the mountain area of North China were studied. The results showed that the total density of sample plot A and total basal area were the smallest for 1 007 plant, hm2 and 24. 446 4 m2 · hm-2 , sample plot C was the maximum for 1 525 plant· hm-2 and 47. 280 2 m2 · hm-2 ,sample plot B was middle; larch in sample A had the largest diameter at breast height for 18.6 cm,sample B for a minimum of 18.1 cm,while the height of tree was on the contrary. The average angular scale of sample A was 0. 358 8,a uniform distribution, forest was in a relatively stable state,larch stand was in a state of uniform distribution; average angular scale of sample B was 0. 523 8, clumped distribution, larch stand was uniform distribution in forest; angular scale of sample C was 0. 508 5, random distribution,larch was the uniform distribution in forest, spruce was clumped distribution, Acer elegantulum and rowan were in random distribution. The average size ratio of sample A was 0. 333 1 ,size ratio of the larch and birch had little difference,that stand spatial differentiation was relatively small,the dominance of two species was not much difference; size ratio of sample B was 0. 487 2, larch had the advantages, Quercus mongolica, aspen, Acer elegantulum and rowan were at a disadvantage, other species in the middle,and the size ratio of each species was difference; size ratio of sample C was 0. 484 5 ,spruce and larch were in the absolute superiority; mixed degree of sample plot A was 0.47,which belongs to the kind of serious mingling; mixed degree of sample B was 0.37, mixed degree was relatively low; mixed degree of sample C was 0.83 ,its species composition was more diversified, more stable structure, use of space was more fully.