Development of Univariate and Bivariate Form Height Tables for Eucalyptus Plantations in Guangxi
To accurately calculate timber volume in Eucalyptus plantations using stand form height tables with the aim of providing theoretical support for harvesting operations and forest resource planning and design. This study developed both univariate and bivariate form height models based on the mathematical relationships between average diameter at breast height (DBH),average tree height,and form height values from 234 sample plots. The univariate form height model was expressed as {Hf=129.99766×[(1-exp(-0.0037249×H)]0.978321},while the bivariate form height model was given by (Hf=0.577152×H1.20331×D-0.28581). The results indicated that for various Eucalyptus species,production areas,and ranges of diameter and height,the univariate form height model achieved a total relative error (TRE) and average systematic error (ASE) within±2％,an mean percentage standard error (MPSE) below 4％,and a prediction accuracy (P value) exceeding 98％. Similarly,the bivariate height model had a TRE and ASE within±2％,an MPSE under 3％,and a prediction accuracy surpassing 99.5％. Both models met the technical requirements for compiling height tables,with the bivariate model demonstrating overall superior performance compared to the univariate model.
万方数据
维普
