Trunk profile equations evaluated for Corymbia citriodora Hill & Johnson

Abstract

Profile equations of the trunk of the trees make it possible to quantify different wood uses that can be used in a specific forest stand. They come from the adjustment of taper models, referred to as: tapering, thinning, shape and, or profile of the trunk or shaft. Since there are no studies on the use of trunk profile equations in Brazilian plantations with Corymbia citriodora, this study aimed to verify the fit of a large number of models for this important forest species. 35 cubed trees were used with direct measurements of the diameter of the trunk in the positions: 0.2 m, 0.4 m, 0.7 m, 1.3 m, 2.7 m and every 2 meters up to an approximate value of 1.0 cm shelled. As statistical criteria for evaluating the trunk profile equations generated for C. citriodora, the following were considered: adjusted determination coefficient, standard error of the estimate, graphical distribution of the residues, mean of the absolute deviations, standard deviation of the differences, sum of the squares of the residues relative, mean of the percentage deviations, square root of the mean error, bias and multiple linear correlation coefficient. It was concluded that, to describe the profile of the trunk of C. citriodora, the equations generated by models that are very widespread in Brazil presented an unsatisfactory performance and that six models that are still under-tested or without application in the country stand out.

Keywords

• validação cruzada. taper. multiprodutos madeireiros.