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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