基于自稀疏理论的杉木人工林密度指标研究

Comparative Study on Stand Density Measures Based on Self-thinning Theory for Chinese Fir Plantation

量化林分密度是精准林业实现的基础。选择合适的林分密度指标用于杉木人工林的模拟和预测研究。基于同一套数据构建3个林分密度指标,根据这些指标的理论分析和动态变化规律进行选优。理论上,Reneike林分密度指数(SDI)和Curtis相对密度(RD)可互相转换,SDI可作为Nilson密度(SD)指标的特例;杉木人工林分的实证结果表明,SD指标的动态变化规律优于传统的SDI和RD密度,更能反映林分的生长规律;而且具有与立地质量不相关的比较优势。Nilson密度指标可用来模拟和预测杉木人工林的生长和收获。

The relationship between yield and stand density is of critical importance in precision forestry. A nec- essary first step is how to accurately quantify the stand density. The objective of the paper aimed to find out the optimum measure from three relative stand density index based on self-thinning theory, such as Curtis＇ s, Re- neike＇ s and Nilson＇ s stand density. These density ：pleasures were developed through the same data from experi- ment of Chinese Fir plantations （ Cunninghamia lanceolata （ Lamb. ） Hook）, and selected according to theoreti- cal analysis and practical verification. Theoretically, Curtis＇ s relative stand density （RD） is equivalent to ac- cepted stand density index （SDI）, and SDI can be viewed as a special sample of Nilson＇ s stand density （SD）. A case of Chinese Fir plantations showed that SD measure was superior to conventional SDI and RD for reflecting the actual dynamic change rule of stand density. Additionally, it had less correlation with site quality than SDI and RD measures. The SD measure is able to apply for modeling and predicting of planted Chinese Fir all over site index and age.