广州三种森林粗死木质残体(CWD)的储量与分解特征

Characteristics of storage and decomposition of coarse woody debris (CWD) under three forests in Guangzhou

粗死木质残体(Coarse Woody Debris,CWD)对森林生态系统的稳定性具有不可忽视的贡献。对广州3种森林CWD的储量与分解特征进行了调查分析,结果表明:(1)CWD储量及其与相应森林总生物量比值均表现为常绿阔叶林>针阔混交林>针叶林;枯立木与倒木为CWD的主要成分,其中,针叶CWD主要物种为马尾松(Pinus massonianai),阔叶CWD物种主要为荷木(Schima superba)与黄杞(Engelhardtia chrysolepis)等。(2)CWD径级主要集中在<10cm的范围内,存在状态主要为中级腐烂状态,干扰与竞争是3种森林CWD产生的主要因素。(3)针叶林、针阔混交林与常绿阔叶林CWD的分解常数k分别为0.0244、0.0407和0.0487,即分解速率为常绿阔叶林>混交林>针叶林;随着CWD的分解,N、P与木质素的含量逐渐升高,C、C/N与木质素/N呈降低趋势。

Coarse woody debris（CWD） has a significant contribution to the forest ecosystem stability.Characteristics of storage and decomposition of CWD under three forests in Guangzhou were researched.The results showed that,（1） CWD storage and the ratio of CWD storage to total forest biomass were in the order evergreen broad-leaved forest 〉 mixed conifer and broad-leaved forest 〉 conifer forest.CWD of the three forests were mainly comprised of snags and logs.The conifer tree specie of CWD was mainly Pinus massonianai.The broad-leaved tree species of CWD were mainly Engelhardtia chrysolepis,Schima superba,etc.（2） The most of diameters of CWD were less than 10cm.Decay state of CWD was mostly in middle decay class.Interference and competition were the main origins of CWD under the three forests in Guangzhou.（3） Decomposition rates of CWD for the three forests were 0.0244,0.0407 and 0.0487 respectively,and they were in the order evergreen broad-leaved forest 〉 mixed conifer and broad-leaved forest 〉 coniferous forest.Furthermore,N,P and lignin contents increased while C,C/N and lignin/N decreased gradually with the decomposition of CWD.