林分密度管理图编制的研究

云南松、华山松是西南地区的主要用材树种。为了研究林木密度与林木生长之间的关系，更好地经营管理好云南松林和华山松林，在引进国内外编图的理论和方法的基础上，我们编制了滇中地区、南盘江林区的云南松和广元林区的华南山松人工林林分密度管理图。按典型选样法所设置的样地，基本能代表该地区云南松和华山松的生长情况，其中，滇中地区云南松林内设置样地493块，南盘江林区云南松林内设置样地305块，广元林区华山松林内设置样地252块。本文不仅在数据惧和整理方法上做了说明，而且以数表的形式了说明了数学模型的选择以及最大密度线、等树高线、等直径线、等疏密度线和自然稀疏线的绘制方法。成图后进行了理论和适用精度检验，其理论精度均在91％以上，适用精度均在85％，证明本设计适用于该林区。该图可用于抚育间伐、资源清查、生长量预测及造林设计等。

A STUDY ON THE STAND DENSITY CONTROL DIAGRAMS

Pinus yunnanensis and P.armandii are the main timber trees in southwest area of China.In order to study the relation between stand density and forest growth and manage the forests of P.yunnanensis and P.armandii well,theau- thors have made a stand density control diagram of the P.yunnanensis forest in central Yunnan and the Nanpanjiang district and that of P.armandii forest in Guangyuan on the basis of the theory and method used at home and abroad. The sample plots made through typical selection can express the growth situation of P.yunnanensis and P.armandii in these areas.Theauthors have made 493 sample plots of P.yunnanensis in central Yunnan,305 in Nanpanjian district and 252 of P.armandii in Guangyuan. This paper has elucidated not only the method of data collection and arrangement,but also the selection of the mathematical model and the drawing method of the full density curve,equal height curve,equal diameter curve, density control curve and the natural thinning curve by means of mathematical tables. The authors have tested the precisions of the diagrams in theory and prac- tice after making them.As a result,the oretieal precision is above 91% while the pratical one is above 85%.The result verifies that the diagrams adapt themselves to the above forest areas. The diagrams can be used in improvement cutting,forest inventory,growth forecasting and afforestation design.