胜山阔叶红松林粗木质残体空间分布格局

Spatial point pattern analysis for coarse woody debris in a mixed broadleaved-Korean pine forest in Shengshan,China

为探究胜山阔叶红松(Pinus koraiensis)林粗木质残体(Coarse woody debris,CWD)的形成过程及机制,采用点格局分析法对10.4 hm^(2)大型样地内不同分类的CWD的空间格局、空间关联性进行了研究。结果表明:(1)总CWD在0—7 m尺度聚集分布,7—50 m尺度随机分布。(2)腐烂等级5级CWD、倒木、伐根在所有尺度随机分布;其他CWD随尺度增大由聚集分布转为随机分布,但格局尺度不同(在2—10 m之间)。(3)大、中径级与小径级CWD在0—4 m、0—6 m尺度正相关;高腐烂等级与低腐烂等级CWD在0—5 m尺度以内正相关;枯立木与倒木在0—4 m尺度正相关;落叶松(Larix gmelinii)CWD与小径级、腐烂等级2级的红皮云杉(Picea koraiensis)CWD在0—3 m尺度正相关,与中径级、腐烂等级1、2级在13—16 m尺度负相关。胜山阔叶红松林CWD的形成是由树种特性、小尺度的个体竞争、大尺度的自然衰老、外界干扰、生境异质性等共同决定的;大、中径级对小径级CWD、先形成对后形成CWD、枯立木对倒木具有一定的正向影响,落叶松对红皮云杉CWD在小尺度有正向影响,而在稍大尺度有负面影响;在一定程度上揭示了该林型CWD的形成过程和机制。

To investigate the formation process and mechanism of coarse woody debris(CWD) in the mixed broadleaved-Korean pine forest,point pattern analysis was used to study the spatial distribution and spatial association of CWD of different categories within a large permanent plot of 10.4 hm^(2).The results showed that:(1) Overall,CWD exhibited an aggregated distribution at scales of 0—7 m,which transitioned to a random distribution as the scale increased.(2) The CWD of decomposition level 5 and logs exhibited a random distribution at all scales,while other CWD shifted from an aggregated distribution to a random distribution,but with different pattern scales(between 2—10 m).(3) Medium diameter class CWD and small diameter class CWD,as well as high decomposition level CWD and low decomposition level CWD,changed from being positively association(0—6 m) to being independent.Further investigation revealed that there was positive association(0—5 m) between high decomposition level CWD and low decomposition level CWD within each diameter class.Additionally,a positive association(0—4 m) was observed between decomposition level 2 CWD of large diameter class and small diameter class.Only the snags and logs had positive correlation(0—4 m).The association between CWD of Larix gmelinii and Picea koraiensis transitioned from positive(2—4 m) to negative(12—17 m),and then to independent.Positive correlations were found between CWD of Larix gmelinii and small diameter class,as well as decay class 2 of Picea koraiensis at scale of 0—3 m,while negative correlations were observed between CWD of Larix gmelinii and mid-diameter class,decay class 1 and 2 of Picea koraiensis at scale of 13—16 m.The formation of CWD in the mixed broadleaved-Korean pine forest may be attributed to tree species characteristics,individual competition at small scales,natural aging,external disturbances,habitat heterogeneity,and other factors.Large and medium diameter classes have a positive influence on small diameter class,earlier mortality has a positive effect on later mortality,the snags have a positive impact on logs.Larix gmelinii has a positive influence on Picea koraiensis individuals at a small scale but a negative influence at a slightly larger scale.This study provides insights into the formation process and mechanism of CWD in this forest type.