Avaliação de funções de afilamento e sortimentos para Mimosa scabrella Bentham em povoamentos nativos da região metropolitana de Curitiba/PR

Abstract

This study was accomplished with the following objectives: 1) to evaluate the acuracy of non- segmented polynomial models to estimate diameters and volumes along the stem of Mimosa scabrella, by diameter class, by age, and by the total of the data; 2) to if verify the if best model to estimate diameters is also the best to estimate volumes; 3) to proceed the validation of the models of better acuracy for volume estimate with trees cubed through the technique of water displacement (xilometer); 4) evaluation of the taper equantions to estimate volumes of multiple products of Mimosa scabrella wood; 5) to test the possibility of grouping the models in the different age classes through the identity test. The data base was composed by 174 trees of Mymosa scabrella, where 121 trees were cubed by the method of Hohenadl with ten sections and 53 trees by the method of water displacement (xilometer). All sample trees came from the Meteropolitan Area of Curitiba/PR. The 121 trees were divided in 5 diameter classes and 4 age classes. It was proceeded the adjustment of three non-segmented taper models for each diameter class, for age class and for the total group of data. The tested non-segmented models were those from Schöepfer (1966), Hradetzky (1976) and Kozak, Munro and Smith (1969). The acuracy of the tested models for the estimates was evaluated through the following statistics: graphic analysis of residual adjusted R2, standard error of estimate in percentage (Syx%) and graphic analysis of average profiles, just used to verify if the fittings are satisfactory in a general way. Complementary the following statistics were calculated: deviation (D), standard deviation of the differences (SD), summ of squares of relative residues (SQRR) and percentage of residues (RP) in order to have a detailed analysis of the performance of estimates along of the whole stem. Starting from these complement sy statistics a ranking was performed to detect the model that propitiated more accurated estimates of diameter sand volumes along the stem. The volumes of the 53 xilometered trees were then estimated through the equation of better performance for the grouped data by diameter class and by age, as for the total of trees. The estimated volumes of these 53 trees were compared with their respective real volumes through the c2 estatistic. The assortment was done for individual ages and for grouped ages through the better fittings equations for volumes estimates, and later on extrapolated to hectare. In the attempt of grouping of the classes of age the identity test was used, facilitating to do 11 combinations. After the analysis it was concluded that the model from Hradetzky (1976) was the best for estimating diameters will as estimating volumes, in almost all diameter classes and ages. It was also the best for the total data set. The model from Kozak et al. (1969) presented bias estimating diameters and volumes for all classes and for the total data set. The validation test proved that taper equations of best performance for diameter estimation along the estem ware also the best for volume estimation. Therefore they can be used to do the assortment. In general the obtained assortments presented great variation among and inside of the ages, caused by the oscillation of the reason height/diameter The identity test for the three tested models showed that they can be grouped for the age classes 3 and 4. the age classes 1 and 2 only can be grouped for the 5º degree and for the Kozak models.