Comparison of lodgepole pine yield tables
Iterative solution of equations from Johnstone's variable-density yield tables for lodgepole pine permitted estimates of stand development index (DI) and productivity index (PI) from the volume, quadratic mean of diameter at breast height, basal area, or dominant–condominant height associated with a particular stand density at a particular age. Using such estimates, the yield tables of Smithers were compared with those of Johnstone. PI values associated with each of Smithers' site indices were calculated for British Columbia and Alberta. Results suggested that Johnstone's equations could be used in lodgepole pine stands in both British Columbia and Alberta, for PI values from 0.7 to 1.2, for densities up to 2500 stems acre−1 at age 70, and for ages up to 120. This considerably extends the range of application of these equations.