天目山针阔混交林树冠重叠关联因素变化特征OA

This study investigates the influencing factors and dynamic characteristics of tree crown overlap in the coniferous-broadleaved mixed forest of Tianmu Mountain,aiming to elucidate the ecological relationships and intrinsic mechanisms among trees,thereby providing a theoretical foundation and technical support for the sustainable management of such forests.On the basis of the plot survey data in 2011 and 2023,we delineated the tree crown growth space,determined the crown overlap relationships,and constructed the crown overlap coefficient(COC)to quantify the proportion of trees with overlapping crowns.Furthermore,we analyzed the correlations and dynamic characteristics of COC across multiple dimensions,including tree diameter at breast height(DBH),tree height,crown width,timber volume,species pairs,stand density,and tree productivity.The results indicated that crown overlap was prevalent among most trees,with the proportion increasing from 77%in 2011 to 88%in 2023.Moreover,the crown overlap enhanced as the stand developed.Trees with small to medium DBH,moderate height and crown width,and low timber volume exhibited higher COC values,which increased notably with tree growth.The correlations of crown overlap with DBH,tree height,crown width,and timber volume were weak and remained relatively stable.The tree crown overlap exhibited significant species-specific associations,with higher overlap observed among species such as Quercus fabri,Symplocos sumuntia,and Quercus spp.,while Cunninghamia lanceolata demonstrated relatively low crown overlap.Crown overlap showed a complex relationship with stand density,which transitioned from a weak correlation to a significantly positive correlation as the stand developed.Furthermore,crown overlap exerted a negative effect on forest productivity.