Assessing the accuracy of tapering and volume models

The aim of this study was to assess the accuracy of tapering and volume equations for the species Qualea albiflora Warm. (cambará), in areas of the municipality of Santa Carmem, in the northern region of the state of Mato Grosso. Fifty-eight trees of the species were rigidly cubed in order to obtain the real volumes, using the Smalian method, and to adjust the tapering and volume models compatible with Schöepfer, Kozak, Hadrezky and Max & Burkhart, and the traditional Schumacher total volume model. The accuracy of the models tested was assessed using the adjusted coefficient of determination, the standard error of the estimate and the graphical analysis of the residuals. The Max & Burkhart model was the most accurate for describing the tapering and compatible volume of the Qualea albiflora species, and the Schumacher model was fairly accurate for estimating the total volume.