期刊
ARID LAND RESEARCH AND MANAGEMENT
卷 20, 期 2, 页码 147-159出版社
TAYLOR & FRANCIS INC
DOI: 10.1080/15324980500546015
关键词
volume estimation; regression analysis; variable top height; fitting; validation
Eucalyptus hybrid is one of the most important tree species adopted for large-scale commercial plantations by State Forest Departments, nongovernmental organizations (NGOs), and farmers in India. But accurate volume equations are not available. The aim of this study was to develop equations for predicting individual tree total volume and merchantable volume for E. hybrid. A total of 114 trees with ages between 1 and 19 yr and breast height diameter (dbh) between 4.7 and 33.1 cm were felled for model fitting and analysis. Linear and nonlinear equations were used to model the relationship of total volume with dbh, and with dbh and total height of the trees. Merchantable volume equations for estimating merchantable volume to any minimum bole height are also presented. For this, diameters were measured at different heights along the stern including height to the base of crown. The equations tested fitted the data well. The adjusted R and root mean squared error indicated that for estimation of V-o from dbh, and from dbh and total height, non-linear equations performed better. These equations may also be recommended for use because of their simplicity and ease of use in the field. In general, nonlinear models only with diameter and with diameter & height overestimated total volume with a mean difference between measured and predicted values of 0.48% and 0.15%, respectively. The variable top-height volume equation tended to underestimate the merchantable volume with all average difference of 1.74% between measured and predicted volume. Model validation with all independent data set indicated that for greater accuracy models should be calibrated with local data. Based on the model validation with sample data and oil the models biological logic (volume depends oil tree diameter as well as oil height), model incorporating diameter as well as height was considered to be more appropriate for general volume estimations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据