FITTING, SELECTION AND MODEL IDENTITY TEST FOR VOLUME AND NUMBER OF FENCE POSTS OF CANDEIA (Eremanthus erythropappus)

Abstract

The objectives of this study were: to fit and select statistical models for estimating the total volume, with and without bark, and number of fence posts in three counties of Minas Gerais State, as well as, to define the stack factor per diameter class and to evaluate, by means of the identity model test, the possibility of using the same mathematical model for all regions. Data base were obtained from a scaling of 174 trees grouped in six diameter classes within the three study regions. The scaling was carried out using the xylometer method (water displacement technique). The accuracy of the models was evaluated using the coefficient of determination, the mean standard error of estimate, and the graphical analysis of residuals. The Spurr logarithm model was selected as the best one for all tested variables. Considering the variables total volume, with and without bark, the identity test showed the possibility of using the same model for Aiuruoca and Ouro Preto counties whereas for the variable number of fence posts, the identity test showed that there is no possibility of grouping for any combination among the counties.