中国森林凋落物不同组分异速比例关系

Allometric relationships among different components of forest litterfall in China

森林凋落物(litterfall)是森林植物在其生长发育过程中新陈代谢的产物,在物质循环和能量流动方面起着重要作用。该文利用已发表的我国主要森林凋落物的研究数据,分析了不同组分(叶、枝和繁殖器官)凋落物量之间及其与总凋落物量之间的异速比例关系。结果表明:我国森林叶、枝和繁殖器官的平均凋落物量分别为3 810.34、1 019.07和767.95 kg·hm–2·a–1;温度、降水量、林龄对森林凋落物量均有一定程度的影响,其中温度对各组分凋落物量的影响最大。叶凋落物量(LL)与总凋落物量(LT)之间呈等速生长关系(LL∝LT0.96),繁殖器官和枝的凋落物量(分别为LP和LB)与LT之间呈异速比例关系,分别为LP∝LT1.84和LB∝LT1.61。不同组分凋落物量之间具有显著的异速比例关系,其异速指数均小于1.0。不同林型(常绿林和落叶林)各组分凋落物量之间的异速比例关系无显著差异。了解不同组分凋落物量与总凋落物量之间的异速比例关系可以为更加精确地估算森林生产力提供理论依据。

Aims Litterfall is a measure of the metabolic product of forest plants during their growth. It plays an important part in the fluxes and recycling of matter and energy. The metabolic theory of ecology posits that there exist al- lometric relationships among different organs of a plant. However, all these scaling relationships do not take into account the potential contribution of litterfall, and hence much remains unknown about the allometric relation- ships among the different components of litterfall. In this study, we analyze the allometric relationships between component as well as the allometric relationships of the total litterfall with different components. Methods We compiled data on forest litterfall from the literature published in Chinese journals and divided these data into evergreen forests and deciduous forests for analysis of the allometric relationships between components as well as the allometric relationships of the total litterfall with different components.Important findings We found that the average amount of litterfall was 3 810.34 kg·hm–2·a–1, 1 019.07 kg·hm–2·a–1, and 767.95 kg·hm–2·a–1as leaves, branches, and propagules, respectively. Compared with precipita- tion and stand age, temperature had a greater effect on forest litterfall production. An isometrical relationship was observed between leaves and the total litterfall, as LL ∝ LT 0.96（LL, leaf litterfall; LT, total litterfall）; whereas an allometric relationship was found between the propagules and the total litterfall as LP ∝ LT 1.84（LP, propagule lit- terfall）, and between the branches and the total litterfall as LB ∝ LT 1.61（LB, branch litterfall）, respectively. Signifi- cant allometric relationships were also observed among different components, with exponents all less than 1.0 in each case. Allometric relationships of the total litterfall with different components were approximately the same between the evergreen forests and the deciduous forests. The allometric relationships found in this study provide valuable insights into the investigation and estimation of forest productivity.