1887

n Southern African Forestry Journal - Analysis of individual tree volume equations for in Munessa forest, Ethiopia : scientific paper

Volume 2005, Issue 203
  • ISSN : 0038-2167
USD

 

Abstract

Three different volume equations were fitted to individual tree volume (V) data collected on 260 <I>Cupressus lusitanica&lt;/I&gt; trees from 49 plantations in Munessa Shashemene Forest, Ethiopia. The data were first split randomly into equation development and equation testing data sets of equal size. Diameter at breast height (D) and height above the stump to the tree tip (H) were used as independent variables to predict volume over bark from a stump height of 30cm to the tip of the tree. The parameters, standard errors and mean square errors for each of the three equations were estimated with weighted least squares regression analysis using the modelling data set. The equations were then compared on the basis of fit statistics using the equation testing data set. The equation form V = <SPAN lang=AF style="FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol"><SPAN style="mso-char-type: symbol; mso-symbol-font: Symbol"&gt;b&lt;/SPAN&gt;&lt;/SPAN&gt;&lt;sub&gt;0&lt;/sub&gt; + <SPAN lang=AF style="FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol"><SPAN style="mso-char-type: symbol; mso-symbol-font: Symbol"&gt;b&lt;/SPAN&gt;&lt;/SPAN&gt;&lt;sub&gt;1&lt;/sub&gt;(H/D)&lt;sup&gt; <SPAN lang=AF style="FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol"><SPAN style="mso-char-type: symbol; mso-symbol-font: Symbol">b</SPAN></SPAN>2</sup>D<sup>2</sup>H+ <SPAN lang=AF style="FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol"><SPAN style="mso-char-type: symbol; mso-symbol-font: Symbol"><font size="5"&gt;e&lt;/font&gt;&lt;/SPAN&gt;&lt;/SPAN&gt;&lt;sub&gt;1&lt;/sub&gt; was the best and, therefore, it was fitted to the combined data set.

Loading full text...

Full text loading...

Loading

Article metrics loading...

/content/forest/2005/203/EJC33983
2005-03-01
2016-12-10

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error