山杨和白桦天然林凋落物周转比较

通过对帽儿山白桦和山杨天然次生林凋落物产量、林地枯落物现存量及其周转时间进行研究,结果表明:(1)白桦林和山杨林的年凋落量分别为435g!m-2和464g!m-2,两种林型凋落物的主要组分均为叶,占60%以上,其次为枝和碎屑,繁殖器官最少;(2)白桦林总枯落物现存量为1 421g!m-2,林地枯落物、小枝、未分解层和半分解层现存量各占1/3;山杨林总枯落物现存量为1 647g!m-2,林地枯落物小枝、未分解层和半分解层现存量比例分别为25%、45%和30%;(3)白桦林小枝、叶、碎屑周转时间分别为17.4a、1.6a和8.1a;山杨林小枝、叶、碎屑周转时间分别为6.9a、12.5a和11.5a,白桦和山杨林总体周转时间接近,分别为3.3a和3.5a。

Comparison on Turnover of Litter for Natural Forest of Populus davidiana and Betula platyphylla

Litter yield,standing crop of forest litters and turnover time of Populusdavidiana &tulaplatyphylla in Maoer mountain were studied.Result shows that (1)the amount of annual litter of Betula platyphylla &Populus davidiana is 435 & 464 g m-2 ,the main component of two types of forest leaf litter are more than 60 percent,fol-lowed by branches and debris,reproductive organs minimum;(2 ) the standing crop of total litter for Betula platyphylla forest is 1 421g m-2 ,forest litter,twigs,undercomposed layer and the layer of semi-decomposed bio-mass constituted 1/3;the standing crop of total litter of Populusdavidiana is 1 647 g m-2 ,forest litter of twigs are not decomposed layer and the layer of semi-decomposed biomass ratio is 25%,45% and 30%,respecticely;(3)turn-around time of twig,leaves,debris for Betulaplatyphylla is 17.4 a,1.6 a and 8.1 a;twigs,leaves,debris turnaround time of Populusdavidiana is 6.9 a,12.5 a &11.5 a.The total turnover time of Betulaplatyphylla &Populusda-vidiana is so near,being 3 .3 & 3 .5 a.