巴朗山川滇高山栎群落水平结构的海拔梯度特征

The Altitudinal Gradient Characteristics of Level Structure in the Quercus aquifolioides Community in the Balang Mountain in Wolong Nature Reserve,China

采用标准地法对卧龙自然保护区4个海拔梯度川滇高山栎群落水平结构进行了研究,结果表明:(1)在各个海拔梯度上物种以川滇高山栎为主,其相对密度分别为61.40、65.67、77.21和62.27;随海拔升高伴生木本植物种类逐渐减少,从11种减少到3种。(2)有随海拔升高,川滇高山栎群落物种相对频度大于2.0以上的物种数量具有先升高后降低的趋势,川滇高山栎是各个梯度出现频度最大的物种。(3)川滇高山栎群落物种重要值大于5.0以上的物种数量具有随海拔升高先升高后降低的趋势,川滇高山栎在从低到高的4个海拔梯度上重要值分别为68.47、80.37、119.93和84.01。(4)林分平均树高和林分平均地径具有随海拔升高而降低的趋势,海拔每升高100 m树高和基径分别平均降低0.18 m和0.22 cm。(5)按株频度计算,在巴朗山阳坡各个海拔梯度的川滇高山栎种群多为聚集分布;而丛频度计算,在高海拔和低海拔地带川滇高山栎种群格局呈聚集分布,在中等海拔区域川滇高山栎种群格局呈随机分布或均匀分布。

Using the methods of field plot investigation, researches were directed towards the characteristics of level structure in Quercus aquifolioides communities, which were distributed along altitudes from 2 400 m to 3 600 m,and in the sunny slopes of the Balang Mountain in Wolong Nature Reserve. The results are summarized as follows： （ 1 ） The main species is Quercus aquifolioides in Quercus aquifolioides communities along altitudes from 2 400 m to 3 600 m, and the relative density of woody layer of Q. aquifolioides community is 61.40,65.67,77.21 and 62.27 respectively; the companion species of woody plants gradually decline with altitudinal increase, from 11 species to 3 species. （2） There is a trend of the species number of the relative frequency （ 〉 2. 0） of woody layer of Q. aquifolioides community deeline with altitudinal increase in the sunny slopes of the Balang Mountain, and the species of the maximum relative frequency is a species of Q. aquifolioides at different ahitudinal gradients. （3）There is a trend of the species number of important values （ 〉 5.0 ） of woody layer of Q. aquifolioides community decline with altitudinal increase in the sunny slopes of the Balang Mountain, and its important values are 68.47, 80. 37,119. 93 and 84.01 respectively. （4）There is a trend of tree height decline with altitudinal increase in the sunny slopes of the Balang Mountain. The average height of tree height of Q. aquifolioides decreases almost linearly from 3.81 m at 2 200 m elevation to 1.45 m at 3 600 m elevation, with an average decrease of 0. 18 m per 100 m of elevation. The average basal diameter also decrease linearly with the altitudinal increase. It decreases from 5.03 em at 2 200 m to 1.93 cm at 3 600 m, with an average decrease of 0. 22 em per 100 m of elevation. （5） There are most types in clumped distribution according to the tree frequency figuring out the distribution pattern of Q. aquifolioides population along altitudes; This is a clumped distribution according to the clump frequency figuring out the distribution pattern of Q. aquifolioides population in high altitudes or low altitudes, and a random distribution or a regular distribution in the mid-altitudinal zone.