Ponderosa Pine in the Second Cutting Cycle

Abstract A 480-acre sample plot logged in 1909 and again in 1939 was remeasured in 1944 for the first 5-year record in the second cycle. Net annual increment per acre declined from a high of 115 board feet in the second 5-year period to 52 in the sixth. According to the 20-year trend before cutting it would have declined further to about 40 board feet in 1944, but it rose instead to 67 notwithstanding a reduction in the volume of growing stock by 50 percent. Analysis of trends before and after the second cutting indicate that if the second cut had been made 10 years earlier net increment today would be at least 50 percent higher than it is. Comparison of three methods of cutting indicate that marking must be governed by silvicultural principles applied to each individual tree rather than a blanket system.