长白山天然云冷杉异龄林林分结构动态变化研究

以云冷杉针阔混交林为研究对象,利用固定样地11次22a的调查数据,研究其林分结构变化,分析林分株数密度、每公顷胸高断面积、树种组成、直径分布、林分年龄、新增木与枯死木以及幼树更新动态变化特征。结果表明:林分林木株数及每公顷胸高断面积变动幅度较小,分别增加了2.96%和3.78%;林分针阔比例一直稳定在5∶5;样地林木直径分布呈倒J型曲线;枯死木与新增木主要集中在杂木与云杉2个树种,枯死木主要集中在小径级6～10cm、10～20cm,枯死木株数随着径级增大而减少;更新苗株数总体减少了50%,而更新的主要树种冷杉、红松、云杉没有变化;林分平均年龄为78.4a,林木年龄在15～197a,跨度很大,各树种年龄由大到小依次为红松>冷杉>椴树>杂木>云杉。

Dynamic Change of Spruce-fir Natural Forests in Changbai Mountain

A fixed sampling plot of spruce-fir natural forest with an area of 0.2 hectare in Changbai Mountain in Northeast China was selected to collect data for 11 times during 1986 to 2008 to examine the dynamic changes in stand structure.All of the trees bigger than 5 cm DBH were measured and the mortalities,the recruitment and the additions were recorded.The results demonstrated that the stand had a 2.96% overall increase in density and a 3.78% overall increase in basal area.Coniferous species basal area property overall declined and broad-leaved species basal area property overall increased.The stand proportion of coniferous and broad-leaved remained in a stable proportion of 5∶5.The maximum density species change Abies nephrolepis into Picea koraiensis.A.nephrolepis density declined from 180 N/hm2 into 160 N/hm2 but P.koraiensis density increased from 125 N/hm2 into 160 N/hm2.Tilia amurensis remained the maximum basal area species and it had a 33.92% increase.The diameter distribution remained an inverse J-shaped curve between 1986 and 2008.A.nephrolepis and Acer tegmentosum were all bell shaped.Pinus koraiensis,Tilia amurensis,Picea koraiensis were all had an inverse J-shaped curve.The density declined in small diameter individual but increased in middle and big diameter individual.The tree ≥5 DBH recruitment and died species all focused in A.tegmentosum and P.koraiensis throughout the study.The long-term outlook for the P.koraiensis is uncertain due to its high regeneration,high mortality rate and high recruitment.The diameter mortality rate sharply decreased when the diameter increase.The tree age in the stand ranged from 15 to 197,the average stand age is 78.4.The species average age is P.koraiensis>A.nephrolepis>Tilia amurensis>A.tegmentosum>P.koraiensis.