小兴安岭谷地云冷杉林粗木质残体的研究

Coarse Woody Debris(CWD) in a Spruce-fir Valley Forest in Xiao Hinggan Mountains,China

论文以小兴安岭谷地云冷杉林大面积固定样地(9.12 hm2)为对象,分析了粗木质残体(CWD)的物种组成、径级分布、存在形式、腐烂等级。主要结果如下:①CWD的密度为1 097株/hm2,胸高断面积为18.49 m2/hm2,材积为96.25 m3/hm2。②所有CWD个体的径级分布呈典型的倒"J"型,其中红松(Pinus koraiensis)和兴安落叶松(Larix gm elini)呈双峰型,其他主要组成树种呈典型的倒"J"型;从材积上看除了兴安落叶松呈随着径级的增加材积也增加的"J"型分布外,其余主要树种均呈近正态分布,总体上材积呈近正态分布。③云冷杉林主要以干基折断、拔根倒、枯立木、干中折断为主,随着径级的增加枯立木和树段的比例逐渐减少,而根桩和干中折断逐渐增加,拔根倒先增加后减少,干基折断变化不大。④腐烂等级呈近正态分布,且主要分布在Ⅲ、Ⅱ和Ⅳ等级。随着径级的增大,Ⅰ、Ⅱ和Ⅲ等级的比例减少,Ⅳ和Ⅴ等级的比例有增加的趋势。枯立木以Ⅱ、Ⅰ、Ⅲ等级为主,干中折断Ⅲ等级较多,拔根倒、干基折断、树段等相对于其他存在方式各腐烂等级的比例相对均匀,而根桩以Ⅴ等级为主。

This experiment was conducted to understand the species composition,diameter distribution,types and decay classes of coarse woody debris（CWD） on the 9.12 ha of large sampling unit in a spruce-fir valley forest,Xiao Hinggan Mountains.The results indicated that： 1） The density,basal area and volume of CWD were estimated as 1097 stems/ha,18.49m^2/ha and 96.25 m^3/ha,respectively.2） The diameter distribution of all CWD showed typical reverse J-shaped curve.Even though the diameter distribution of CWD of Pinus koraiensis and Larix olgensis presented double-hump-shaped curve,that of the other major tree species displayed typical reverse J-shaped curve.Normal distribution was noticed for the volume of all CWDs.The volume of CWDs from Larix olgensis increased as the increase of diameter with a J-shaped distribution.The volume distribution of CWDs from other major tree species is close to normal distribution.3） Existing types of CWDs were mainly composed of breakage at rootstock,uprooted blow-down,standing die,and breakage at trunk.With the increase of the diameter of CWDs,the percentage of standing die and trunk segment decreased while the percentage of stump breakage at trunk increased.However,the proportion of standing die increased first and then decreased without significant variation noticed for the percentage of breakage at rootstock.4） The distribution of decay class of CWDs followed normal distribution with a concentration on the Classes Ⅲ,Ⅱ and Ⅳ.With the increase of the diameter of CWD,the percentage of ClassesⅠ,Ⅱ and Ⅲ decreased while the percentage of Classes Ⅳ and Ⅴ tended to be increased.The CWD of standing die mainly fell in Classes Ⅱ,Ⅰ and Ⅲ,breakage at trunk fell in Class Ⅲ,and stump fell in Class Ⅴ.Different from others,the CWDs of uprooted blow-down,breakage at trunk,and breakage at rootstock showed relatively even distribution within all decay classes.