Rehabilitation of poorly stocked stands using a microstand approachThis article is part of a larger document. View the larger document here.
Nearly one-quarter of upland oak forests in the Eastern United States are poorly stocked, often as the result of high-grading or repeated diameter-limit harvests. Returning poorly stocked stands to their economic and ecosystem services potential will require innovative rehabilitation practices that are cost-neutral at a minimum. One approach developed for northern hardwoods in Quebec was to recognize that poorly stocked stands are a conglomerate of stand types at the microstand scale (~0.1 acre) and to assign unique treatments to each microstand type. In 2012, we initiated research at five study areas in Connecticut to examine rehabilitation of poorly stocked stands. Rather than a single prescription for the entire stand, we used the decision tree approach to assign treatments at the microstand scale to account for the irregular, spatially patchy structure typical of high-graded stands. The treatment prescriptions incorporated earlier research showing that crop tree release can greatly increase diameter growth and survival, together with timber stand improvement, for the several microstand types commonly found in poorly stocked stands: poletimber, two-aged, sapling, or regeneration. On untreated control plots, 4-year basal area growth of unacceptable growing stock (UGS) was 60 percent greater than for acceptable growing stock (AGS). In contrast, AGS basal area growth was more than double that of UGS on treated plots. Crop tree release on treated plots increased 4-year diameter growth of sapling and pole crop trees, doubling growth of upland oaks. A microstand approach has potential where a commercial biomass market exists or for landowners cutting their own firewood.