秦岭锐齿栎群落数量特征的研究

对秦岭锐齿栎群落的研究结果表明，该群落乔木层可划为两个亚层，其生活型以高位芽占优势。地面芽次之，锐齿栎、华山松的胸径结构呈左偏正态分布；油松的胸径主要以小径级居多；漆树的胸径以大径级的个体占有较大的比例，属于衰退种群；板栗主要是以小径级的幼树和小树为主，处于幼龄向中龄过渡阶段；山杨处于由进展向稳定过渡阶段，属于中幼龄林，林分的胸径结构主要受锐齿栎种群的胸径变化的影响，聚类与排序结果一致，得到6个类型：鞘柄菝葜+蔷薇-栓皮栎+灰榆-锐齿栎群丛；美丽胡枝子+鞘柄菝葜-板栗-锐齿栎群丛；榛子-尖叶四照花+山杨-锐齿栎群丛；樱桃+榛子-漆树-锐齿栎群丛；榛子+蔷薇-华山松-锐齿栎群丛；箭竹-华山松+油松-锐齿栎群丛，表明锐齿栎群落在海拔分布上的连续性和群落类型分布的间断性。

Quantitative analysis on sharp·tooth oak stands in Qinling Mountains

The arbor stratum of Quercus aliena var. acuteserrata stands included two substratums. Phanerophyta synusium was in first position, and hemicryptophyta was inferior to it. The DBH structures of Quercus aliena var. acuteserrata and Pinus armandii were sinister normal school, which could finish self-regeneration under the natural conditions. The small DBH class individuals of Pinus tabulaeformis were dominant, their DBH classes being distributed irregularly and absent very much. The large DBH classes of Toxicodendron vernicifluum took biggish proportion, belonging to declining population. Young trees were the principal individuals of Castanea mollissima, and in transitional age stage from the young to the middle. Populus davidiana was in the transitional stage from progressive to stable and young-middle age stands. The stands DBH structure was mainly influenced by the DBH variety of Quercus aliena var. acuteserrata population. Quantitative classification (ward's method ward) and ordination (PCA) were used to study the community types of sharp-tooth oak. The results showed that the community could be divided into 6 types: 1. Ass. Smilax stans + Rosa multiflora-Quercus variabilis + Ulmus glaucescens-Quercus aliena var. acuteserrata; 2. Ass. Smilax stans + Lespedeza bicolor-Castanea mollissima-Q. aliena var. acuteserrata; 3. Ass. Corylus mandshurica-Populus davidiana + Dendrobenthamia angustata-Q. aliena var. acuteserrata; 4. Ass. Prunus pseudoccrasus + Corylus mandshurica-Toxicodendron vernicifluum-Q. aliena var. acuteserrata; 5. Ass. Corylus mandshurica + Rosa multiflora-Pinus armandii-Q. aliena var. acuteserrata; and 6. Ass. Sinarundinaria nitida-Pinus armandii + Pinus tabulaeformis-Q. aliena var. acuteserrata. Ward's method ward was better for classifying community types than the other clustering analyses in Qinling Mountains. The PCA results were consistent with the clustering, and demonstrated that the sharp-tooth oak stands were influenced by the altitude, site gradient and soil mainly.