森林生态系统中的粗死木质残体及其功能

Coarse woody debris and its function in forest ecosystem.

粗死木质残体 (CoarseWoodyDebris ,CWD)是指所有地上和地下小头直径 >2 .5cm的死木质物 .林分中CWD主要来源于个体的死亡和干扰所造成的死亡 ,在森林群落的生长发育过程中 ,CWD的数量变化呈“U”型 .CWD的分解是动物和微生物吸收养分、淋溶和自然破碎综合作用的结果 ,CWD的分解过程就是其发挥功能的过程 ,在此过程中各阶段都会有不同类型的生物群体利用其提供生境或食物 ;CWD具有吸收和释放养分的能力 ,是植物生长的营养库 ,是森林树木更新的良好介质 ;CWD是许多陆生生物和水生生物的食物来源、栖息地、避难所、哺育地、迁移通道等 ,在生物多样性保持方面发挥着不可替代的作用 ;大CWD的形成过程产生了林窗斑块 ,推动了森林生态系统的小循环 .因此 ,CWD是森林生态系统中重要的结构性和功能性组成要素 ,在保持森林生态系统和水生生态系统的生物多样性及其生态过程完整性等方面起着不可替代的作用 ,应当给予充分的重视 .

Coarse woody debris (CWD) is an important structural and functional element in forest ecosystem.In this paper,the definition,dynamics,and role of CWD in a forest ecosystem were overviewed.CWD include all woody debris above and under the ground with a diameters ≥2.5cm,and mainly comes from the dead trees resulted from competition and disturbances.The biomass of CWD changes like“U”form along with the development of a forest community.The decay rate of CWD is determined by the compound course of the respiration and natural fragmentation.Insects and microorganisms play an important role in the course.CWD basically has two functions in an ecosystem.One is as the nutrition pool for some living creatures,and the other is that the large CWD can form some special habitats for animals and plants.Conclusively these two functions are helpful to reserve the biodiversity and the integrity of ecological process in a natural ecosystem.Gaps are formed while dead trees falling down,and all gaps in a forest succeed one another randomly in the development of a forest ecosystem,which pushes the inner circulation of the forest.Because of the vital roles of CWD in a forest ecosystem,much more attention should be paid in the management of forest ecosystem.