Form Quotient in Estimating Caatinga Tree Volume

Abstract

ABSTRACT The heterogeneity of Caatinga vegetation imposes the need for methodological adaptations to obtain reliable estimates of timber resources. Nevertheless, the number of volumetric studies related to biome trees is still restricted, especially in relation to obtaining form factors and quotients. This study proposes the use of a form quotient (FQ) based on the relationship between diameter at breast height and diameter at diameter at ground level and aimed to evaluate its accuracy in estimating individual tree volume in Caatinga forest. The study area is located in the municipality of Contendas do Sincorá, Bahia, Brazil. Precise scaling volume of 100 trees was performed. The obtained results were compared to the precise scaling volumes in order to evaluate how the form quotient behaved in the volume estimation. A comparative analysis of the FQ efficiency was also performed in relation to two conventionally used methods for volume estimation (form factor and adjusted equation). The mean value of the form quotient was very close to the value of the form factor (0.81 and 0.83, respectively). No significant differences were observed between the estimates and the actual values. The form quotient provided satisfactory results in estimating the total volume of Caatinga trees, and may be indicated for the tree physiognomies of the Caatinga biome.