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以长白山次生杨桦林5hm2样地为对象,以2005和2010年两次调查数据为基础资料,分析了2005—2010年间样地主要树种的组成、数量,死亡个体的径级分布,以及不同生境类型下主要树种的更新特征.结果表明:研究期间,样地内树木胸径(DBH)≥1cm的独立个体的树种数由46种增至47种,新增3个树种,2个树种因仅有的一个个体死亡而消失;独立个体数由16509株减少为15027株,其中,死亡个体数2150株,占2005年个体总数的13%,新增个体数668株,净减少1482个个体;样地树木的胸高断面积由28.79m2·m-2增至30.55m2·m-2,有41个树种的胸高断面积增加,6个树种减少,其中,山杨和白桦的减少量占总减少量的72.3%;小径级个体的死亡量较大,DBH<5cm个体的死亡量占总死亡量的65%,山杨和白桦是大径级个体死亡的主要树种.不同生境类型下个体死亡率差别不大,但各径级间的树木死亡率则有较大差异.
Taking the secondary birch bark of Changbai Mountain as an example, from the data of two surveys in 2005 and 2010, the composition and quantity of the main tree species in the sample plots from 2005 to 2010 were analyzed, as well as the pathological distribution of death individuals and the distribution of different habitat types The results showed that during the study period, the species number of independent individuals with DBH> 1cm increased from 46 to 47 species in the plot, three new species were added, and only two species Individuals died and disappeared; the number of independent individuals decreased from 16,509 to 15,027, of which 21,50 were dead individuals, accounting for 13% of the total number of individuals in 2005; 668 individuals were newly added and the net decrease was 1,482 individuals; The area of chest height increased from 28.79m2 · m-2 to 30.55m2 · m-2, the area of thymus increased with 41 trees and the number of 6 species decreased. Among them, the decrease of aspen and birch accounted for 72.3% The mortality of small-diameter individuals was larger than that of individuals with DBH <5cm, accounting for 65% of the total, and Populus euphratica and Betula platyphylla were the major tree species of large-diameter individuals.Different habitats were not significantly different under different habitat types, However, there is a big difference in the tree mortality rates among different grades.