摘要
四参数油松干曲线式李悦黎（西北林学院杨陵７１２１００）关键词干曲线式，油松，干形反映树干纵断面形状的干曲线式是干形研究中一个非常重要的组成部分。油松干曲线式ｙ＝［ａ０ｘａ１－ａ２＋ａ３／（ａ４－ｘ）］０．５（１）式中：ｙ为树干横断面半径；ｘ为树稍至该...
In the stem form curve formula of Pinus tabulaeformis y=[a0xa 1-a2+a3/(a 4-x)]05, three conditions must be satisfied: (1) a4 is given value beyond the range 0～H, H stands for the tree height; (2) -a2=-a3/a4;(3) The value of expression within radical sign must be positive on any point of the tree stem. Fitting curve based on 129 P.tabulaeformis trees leads to the results: Sharing 89.9% at the condition of R2>0.98, the absolute value of systematic error <3% coves 79.1%,and the absolute value of systematic error is less than 7% at the most. Comparing the tree stem valume derived form formula of stem form curve of the one derived from sectional measurement by means of Smalin's formula, the absolute values of error are not more than 4%, where below 1% shares 76.7% of sample trees. The systematic error of 129 trees is 0.53%. The proposed formula of stem form curve in this paper can reflect the stem form profile of P.tabulaeformis very suitablely.
出处
《林业科学》
EI
CAS
CSCD
北大核心
1998年第4期112-115,共4页
Scientia Silvae Sinicae
关键词
林业
干曲线式
油松
干形
Formula of stem form curve, Pinus tabuleformis Carr, Stem form
