<正>根据南方七省(区)867块杉木实生林标准地原始资料,按不同地位级分别编制了杉木林密度管理图。 各测树因子间相互关系的数学模型:林龄与平均树高关系式为;林龄、密度和平均胸径的关系式为 图象采用直角座标系,以林分平均高、年龄作纵座标,每亩株数(密度)作横座标。基本线为等胸径线和等蓄积量线。参考线为最大密度线和冠幅线。 本图可为杉木林抚育间伐、作业类型设计、杉木生长和产量的预测以及杉木林资源清查提供参考依据。适用范围,年龄5—40年;密度50—500株/亩。

Density Control Diagrams of five site classes of Chinese fir have been corstructed separately. Basic data were collected from 867 sample plots located in 7 Provinces in South China.The relationship between the age and height of a stand is expressed as: H = b0+b1 + b2A2. The model showing the relationship between age, density andmean diameter is D = a + b lg(×100). The latter is applicable to stands aged from5 to 40 years and a density of 1,600 to 6,000 trees per hectare.Diameter lines and stand volume lines are presented’ in the graphs as the main lines, while the full-stocking lines (Nmax. ) and crown width lines (Nc) are demonstrated as reference lines.In practice, these diagrams can be used in the estimation and predication of the mean diameter and yield of a stand.