广东怀集不同树龄红锥叶片功能性状特征OA

Castanopsis hystrix is a vital timber and ecological tree species in China's subtropical regions,and the health of its ancient trees is crucial for ecosystem stability and biodiversity conservation.Currently,research on the variation characteristics and underlying patterns of leaf traits in ancient Castanopsis hys-trix trees of different ages remains insufficient,hindering the scientific formulation of conservation and management measures for these ancient trees.This study selected ancient Castanopsis hystrix trees of var-ying ages from Huaiji County,Guangdong Province.Based on age,the trees were categorized into Grade 1,Grade 2,and Grade 3 ancient trees,as well as reserve resource forests.We measured 11 functional leaf traits—including leaf area(LA),net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),and transpiration rate(Tr).Statistical methods including one-way ANOVA,cor-relation analysis,and principal component analysis were employed to investigate the characteristics and var-iation patterns of leaf traits across different age groups.Results indicate that net photosynthetic rate,rela-tive leaf water content,transpiration rate,stomatal conductance,and leaf volume are key factors for evalua-ting leaf traits in ancient Castanopsis hystrix trees of varying ages.Grade 3 old-growth Castanopsis hys-trix trees exhibited the optimal comprehensive leaf trait performance.As tree age increased,Castanopsis hystrix tree senescence intensified,leading to a gradual decline in leaf photosynthetic capacity.The net pho-tosynthetic rate,stomatal conductance,and transpiration rate of Castanopsis hystrix leaves from the re-serve resource forest were significantly higher than those of old-growth Castanopsis hystrix trees.The to-tal coefficient of variation for 11 leaf trait indicators across different age classes ranged from 2.96%to 34.88%,indicating varying degrees of variability among trait indicators.In forestry production practices,it is recommended that ancient trees with above-ground health diagnosis ratings of Level 3 or higher receive priority revitalization and protection,with enhanced revitalization and rescue efforts.