Resumo. The aim of this paper is to present a new approach for the geometric method, substituting the angular coefficient by the parable index in the generation of taper equations to estimate the volume of individual trees and to compare the volume estimates accomplished, starting from this new approach with the volume obtained by the rigorous cubage of eucalyptus clones. Starting from algebraic modifications in theparable index and considering the same measured points for the original geometric method, expression tapers were developed. Data of 48 plots with 1819 cubed trees, 349 were randomized for the evaluation of the new proposed approach. Two approaches using the parable index were proposed, firstly using two support diameters and secondly using one support diameter in the obtaining of the taper equations. The methods were applied in the other trees and the plot volumes were obtained and compared with the cubed plots volume. The results showed that differences do not exist between the volumes for the proposed methods and the volume rigorous cubage. Therefore, the methods can be used with safety in the forest inventories.