UNASSIGNED: To determine the optimum stand density, a model of maximum size-density relationships was employed to explore the relationship of the self-thinning trajectory with growth, species mixing, latitude, and site conditions during the transition of even-aged pure Chinese fir stands to Chinese fir-dominated mixed forests using stochastic frontier analysis. Data were obtained from a total of 591 permanent plots located in Fujian, Jiangxi, Zhejiang, and Anhui provinces in southern China.
UNASSIGNED: The results showed that (1) the slope of the maximum size-density relationship of Chinese fir-dominated mixed forests increased and plateaued over time; (2) the slope of the maximum size-density relationship of Chinese fir-dominated mixed forests did not deviate from Reineke\'s assumed universal slope of -1.605; and (3) mixing proportion had a positive effect on maximum size-density relationships, and latitude and site conditions had the opposite effect on maximum size-density relationships.
UNASSIGNED: Our findings will provide valuable guidance for the forest management of areas in which even-aged pure stands are being converted to mixed forests (i.e., when broadleaved tree species are planted after thinning to improve overall stand density and promote stand growth).
■要确定最佳林分密度,采用最大尺寸-密度关系模型来探索自变薄轨迹与生长的关系,物种混合,纬度,使用随机前沿分析,将均匀年龄的纯杉木林分过渡到杉木为主的混交林期间的立地条件。数据来自福建共有591个永久地块,江西,浙江,和中国南方的安徽省。
■结果表明:(1)杉木为主混交林最大大小密度关系的斜率随时间增加而趋于稳定;(2)杉木为主混交林最大大小密度关系的斜率未偏离雷内克假设的-1.605的普遍斜率;(3)混合比例对最大大小密度关系有正向影响,纬度和场地条件对最大尺寸-密度关系有相反的影响。
■我们的发现将为将均匀林分转换为混交林的地区的森林管理提供有价值的指导(即,当稀疏后种植阔叶树种,以提高整体林分密度并促进林分生长)。