| 测定单株立木材积的形点法 |
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| 引用本文： | 徐祯祥,廖晓海.测定单株立木材积的形点法[J].林业科学,1990,26(5):475-480. |
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| 作者姓名： | 徐祯祥 廖晓海 |
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| 作者单位： | 河南省林业研究所，河南农业大学林学系，河南农业大学林学系 |
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| 摘 要： | 为了测定单株立木材积,普雷斯勒提出了望高法。其优点是简便易行,缺点是望点较高,通视较差,观测困难,且实际误差较大。希费尔提出了胸高形率法,琼森提出了绝对形率法。它们的优点是精度高,缺点是测定中央直径较麻烦。受上述方法的启示,根据干形特点,我们提出了形点法。用林分速测镜即可简便容易地测出较精确的立木材积。一、形点法的测树原理和方法 (一)基本原理令胸径为D,树高为h,胸高(1.3m)以上树干某点直径为aD(0<α<1),干顶到aD点的干长为h_1,aD到D点的干长为h_2。按孔兹干曲线式y~2=px~r有
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| 关 键 词： | 单株立木材积 测定 测树学 形点 |
FROM REFERENCE POINT METHOD TO MEASURE THE VOLUME OF A SINGLE TREE |
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| Xu Zhenxiang.FROM REFERENCE POINT METHOD TO MEASURE THE VOLUME OF A SINGLE TREE[J].Scientia Silvae Sinicae,1990,26(5):475-480. |
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| Authors: | Xu Zhenxiang |
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| Institution: | Xu Zhenxiang (Henan Forestry Scientific Research Institute) Liao Xiaohai Hou Jianzhi (Henan Agricultural University) |
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| Abstract: | The from reference point is fixed on the position that diameter of the upper stem is equal to 0.5~(1/2) times the diameter at breast height. According to this, the following conclusions are derived: the comprehensive form-exponent of the stem above breast height.
It has been proved in practice that the average system error is -0.44% and standard error is 5.24% by comparing the volume obtained from form reference point method, namely ,with that from theseetional measurement. |
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| Keywords: | Form reference point Comprehensive index |
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