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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
In order to measure the stand volume per plant, Prestler proposed a look-high method. The advantage is simple and easy, the disadvantage is the higher point of view, poor viewing, observation difficulties, and the actual error larger. Schaeffer proposed the method of thorax-height ratio, Johnson proposed absolute rate method. They have the advantage of high precision, the disadvantage is the determination of the central diameter of more trouble. Inspired by the above method, according to the dry-shaped features, we propose a point-shaped method. Quickly measuring the stand volume with the forest quick-measuring goggles is easy and simple. First, the measured point method of tree principles and methods (a) the basic principles of breast diameter D, tree height h, chest height (1.3m) above the diameter of a point for aD (0 <α <1), dry top to aD The stem of a point is h_1, the stem of aD to D is h_2. Press Kongz dry curve y ~ 2 = px ~ r there