Equations are developed for eight conifer species to estimate the stem taper of inside-bark diameters from breast height to the tip of the tree. Separate equations are developed to estimate the diameter inside bark at the stump. Equations are fitted and tested on separate halves of a data set composed of tree taper data from previous studies, both from the forest industry and USDA Forest Service surveys. This composite data set extends from Southern California to the National Forests of southern Oregon.

After an extensive examination of existing taper equations, two taper equations were selected for further analysis, one by Biging and the other by Wensel and Krumland. Coefficients for both equations are given for the eight conifer species examined. Because of a lower residual sum of squares, and a lack of correlation of the residual with the available predictors, the Wensel and Krumland equation is recommended for use.