Effects of Competition,Climate Factors and Their Interactions on Diameter Growth for Chinese Fir Plantations

【Objective】This study aimed to construct a growth model of diameter at breast height(DBH) for Chinese fir plantations based on competition and climate factors,and analyze effects of competition,climate factors and their interactions on DBH growth.The results were expected to provide a reference for the growth of reserved trees after thinning and selective cutting under climatic changes.【Method 】Based on the permanent sample plots in the south of Jiangxi Province,the potential increment equation with multiplicative modifiers was used to construct DBH growth model.The quantile regression technique was used to model the potential DBH increment,and seven environmental factors(mean temperature,maximum temperature,minimum temperature,precipitation,accumulated temperature greater than 5 ℃,elevation,slope) were used to describe the effects of site quality on potential increment.Parameter significance and variance inflation factor were chosen to determine environmental factors,which could be the independent variables.