Ten systems of compatible taper and outside-bark volume equations derived from upper-height-based volume ratio equations were compared with a used segmented-stem
system of compatible taper and volume equations. All the systems were simultaneously fitted to cumulative volume data and taper data for Arizona pine, Aztec pine, Durango
pine, Mexican white pine, and Smooth-leaved pine species in naturally regenerated mixed-species forests in Mexico. The systems derived from volume ratio equations
performed better than the segmented-stem system for most species. The resultant top systems might be easier to implement than the segmented-stem system for predicting
upper-stem height, upper-stem diameter, merchantable volume, and total stem volume for considered species.