Removal intensity and tree size effects on harvesting cost and profitability
Sixteen stands were harvested at intensities (proportion of basal area removed) ranging from 0.27 to 1.00. Logging contractors used chain saws and rubber-tired skidders. Harvested sites were similar in slope and tree size. Harvest cost per hundred cubic feet of wood (CCF) was inversely related to harvest intensity and tree size. Harvesting profitability per CCF was near zero when removing trees averaging less than 8 inches diameter at breast height (d.b.h.). Harvest intensity had the greatest influence on profitability in small-diameter timber. Harvest profitability was greatest when removing large trees at high levels of harvesting intensity. Because of the differences in average tree size removed by different harvesting prescriptions, some prescriptions were more profitable than others. Most profitable for harvesting contractors in our study was single-tree selection in an uneven-aged stand. Less profitable were selection in an even-aged stand, clear cutting, and shelterwood harvests, in that order. Selection at low removal intensities with small trees removed would always be the least favored harvest method with the equipment spreads we observed. Average removed tree size needed to be at least 8 inches d.b.h. to break even.