The aim of this work was to adjust taper models for Pinus taeda using data from complete stem analysis of 120 trees sampled in stands located at the state of Santa Catarina, Brazil. The polynomials with integer and fractional powers and the fifth degree were adjusted to the data set without stratification; they were then stratified in age classes, evaluating the necessity to develop models for age class. Validation was performed and a test of identity was applied on the best polynomial to verify the need for data stratification. The polynomial with integer and fractional powers was selected to estimate diameters at different stem heights. The taper functions obtained for the age classes showed some superiority in comparison with the general equation, suggesting that more accurate estimates of diameters along the stem can be obtained when working with data on age classes.
stem form; assortment; form taper