Abstract:

This study compares financially optimal uneven-aged and even-aged silvicultural regimes of loblolly pine (Pinus Taeda). Uneven-aged regimes which maximize net present value (NPV) are found by quantifying the effects of diameter distribution (Q factor), maximum diameter, cutting cycle, and residual basal area on NPV. For the benchmark inputs, the regime yielding the highest NPV had a maximum diameter of 12 inches, residual basal area of 45 ft2/acre, and a cutting cycle of 11 years. Financially optimal even-aged regimes are taken from published literature of even-aged silviculture. Even-aged and uneven-aged silvicultural regimes are simulated starting from, 1) bare land, 2) a balanced uneven-aged loblolly pine stand, and 3) a mature even-aged loblolly pine stand. For the three starting conditions and selected benchmark variable values, simulation of even-aged silviculture yields NPVs of $877, $2,152 and $3,400 per acre and simulation of uneven-aged silviculture yields NPVs of $644, $2,084, and $2,569 per acre. Sensitivity analysis shows, for the levels of the variables tested, that even-aged silviculture yields higher NPVs than uneven-aged silviculture when starting from bare land or from a mature even-aged stand. When starting from an uneven-aged stand, for the variable values tested, uneven and even-aged silviculture are financially very competitive.

Aside from the aesthetic benefits of avoiding clearcutting under uneven-aged silviculture, non-timber considerations between loblolly pine silvicultural systems are not well documented. Resource professionals hold opinions often in direct conflict with each other regarding the non-timber costs and benefits of even-aged and uneven-aged silviculture when considering wildlife, soil and water, and catastrophic damage events.

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