Several published allometric biomass equations may be available for a particular species. For some applications a method is needed to produce a single equation for the species. Several investigators have produced such an equation by refitting the combined original data used to develop the separate equations. We evaluated a method, previously examined for several hardwood tree species, for producing an equation fit to data generated from the published equations when the original data are not available. For the three tall shrub species groups (Acer spicatumLam.,Amelanchierspp., andSalixspp.) examined, the generated weighted data equation fit the combined weighted data as well as or better than the published equations.