ABSTRACT
The presento study has had as its objective: 1) to evaluate the accuracy of the ratio between volumes compatible with its respective taper function; 2) to evaluate the entire polynomial models and entire and fractionary polynomial models; 3) to study the influence of the diameter classes, site productivity and local effects on the accuracy of the estimates provided by the taper models along the stem profiles of Pinus taeda in the north-eastern region of Parana State. It were cubed 304 trees using a Wheeler's calyper on tripold with a regulated base and with a suunto hypsometer. Near each cubed tree, it was located a plot from which the height of the dominant trees was measured, allowing the accomplishment of site classification of each cubage local. The diameters of cubed trees were assorted in classes with 5 cm intervals. For evaluating the accuracy of the taper models in describing the stem profile, the following statistics were calculated for each measurement position along the stem: coefficient of determination; residual standard error deviation; deviation of the diameters in each position along the stem; standard deviations of the differences of the diameters; sum of square of the relative residue of diameters and the percentage of the residues of the diameters. The main result pointed out that the taper models must be fitted by site productivity and diameter classes, besides the use of the polynomial model of fractionaire and entire power.
Key words:
taper functions; stem profile; Pinus taeda