弄岗北热带喀斯特季节性雨林15 hm^(2)动态监测样地树木死亡特征分析

Analysis of tree mortality characteristics in a dynamic northern tropical karst seasonal rainforest in Nonggang,Guangxi,southern China

以广西弄岗北热带喀斯特季节性雨林15 hm^(2)森林动态监测样地为对象,结合2011年和2016年两次调查数据,分析5年间样地树木死亡个体的数量、径级结构和空间格局特征等。结果显示:2011年至2016年,样地有86.5%的树种出现了个体死亡的现象,死亡个体占个体总数的14.4%;死亡个体的聚集程度随空间尺度的增大而逐渐减弱;小径级个体死亡与周边邻体和环境的关联性较大;竞争是影响弄岗北热带喀斯特季节性云林树木死亡的主要因素。综合来看,北热带喀斯特季节性雨林内树木死亡并非是一个完全随机的过程,而是树木本身特征和生物与非生物环境共同作用的结果。

We conducted two surveys(in 2011 and 2016)of a 15 hm^(2) dynamic monitoring plot in a tropical karst seasonal rainforest in northern Nonggang,China,and analyzed the number,diameter structure,and spatial pattern characteristics of tree mortality in the plot over time.Results showed that from 2011 to 2016,86.5%of the tree species in the plot had individual deaths,accounting for 14.4%of the total number of individuals.The diameter class of dead trees showed an inverted“J”shaped distribution,consistent with the diameter class structure of standing trees.Competition was the main factor affecting tree death.In summary,tree death in the northern tropical karst seasonal rainforest was not a completely random process,but due to the combined effects of tree characteristics and biological and non-biological environments.