人为干扰对大兴安岭北坡兴安落叶松林粗木质残体的影响

比较了兴安落叶松天然林和两种不同干扰类型兴安落叶松林(一次干扰林、二次干扰林)之间活立木蓄积、粗木质残体(CWD)蓄积和组成的差异.结果表明：天然林、一次干扰林和二次干扰林的活立木蓄积量分别为161.6、138.3和114.8 m³·hm^-2，粗木质残体的蓄积量分别为69.77、36.64和32.61 m³·hm^-2.天然林粗木质残体大部分径级在20～40 cm，其中倒木、枯立木分别占总材积的72%和28%；一次干扰林和二次干扰林粗木质残体大部分径级在10～30 cm，其中倒木、枯立木和伐桩分别占各自总材积的70%、14%、16%和57%、15%、28%.人为干扰造成兴安落叶松林粗木质残体蓄积减少，改变了粗木质残体的组成.

Effects of human disturbance on coarse woody debris of Larix gmelinii forest on northern slope of Greater Hinggan Mountains.

An investigation was conducted on the living tree volume, coarse woody debris (CWD) loading, and composition of Larix gmelinii forest along a human disturbance gradient, i.e., no disturbance (natural larch forest), one-time d isturbance (natural forest was disturbed once only), and two-time disturbance (natural forest was disturbed two times consecutively), on the northern slope of Greater Hinggan Mountains. The results showed that under no disturbance, one -time disturbance, and two-time disturbance, the average living tree volume of L. gmelinii forest was 1616, 1383, and 1148 m3·hm-2, and the average CWD loading was 6977, 3664 and 3261 m3·hm-2, respectively . In natural L. gmelinii forest, most of CWD was of 20〖KG-*2〗-〖KG-*7〗40 c m diameter class, among which, fallen logs occupied 72%, and snags and stumps oc cupied 28%; while in one-time and two-time disturbance L. gmelinii forests, most CWD was of 10〖KG-*2〗-〖KG-*7〗30 cm diameter class, with the fallen logs , snags, and stumps occupied 70%, 14% and 16%, and 57%, 15% and 28%, respectivel y. Human disturbance reduced the CWD loading of L. gmelinii forest and altere d the composition of the CWD.