In the United States, private working forests contribute about 280 million cubic meters to domestic annual wood production. In 1993 and 1998, assessments of the sustained yield potential for sawtimber products were conducted on West Virginia’s working private forests. As a result of exploitative harvesting practices, only 27% of the harvests sampled had sufficient residual densities of quality stems and marketable species to sustain another profitable cut during the current rotation. All of the high-value trees had been removed from 56% of the harvests, yet these still contained sufficient volume of low-value residual trees that could be suitable for fibre/biomass products if markets existed. Since that time, other studies in the eastern region continue to indicate that non-sustainable harvesting practices are common on over 80% of private forest ownerships. Ten years of monitoring such sites indicates that rehabilitating these stands requires the removal of residual stems because they impede the growth of most desirable tree regeneration. Creation of biofuel markets for previously unvalued fibre may make these rehabilitation efforts profitable if the economic challenges related to fibre extraction and transport are addressed. New markets for low value trees will also promote sustainable silvicultural practices instead of harvests that only target the largest, most valuable trees. This presentation will discuss the results of long-term studies of non-silvicultural partial harvesting practices and the use of biomass harvesting to rehabilitate degraded forest stands in the central Appalachian region.
Results/Conclusions
The amount of potential woody biomass remaining in West Virginia stands immediately after all high value trees were removed, averaged 50,125 (±10,648) kg/ha; five years later (1998) that amount had increased to 64,359 (±17,575) kg/ha. Ten years after experimental diameter-limit harvesting had been used to remove all trees ≥ 41 cm, growth of Prunus serotina and Quercus rubra saplings in the new cohort was being hindered by overtopping from residual stems. Commercial removal of only the residual sawtimber was not feasible due to stem scarcity and low value. However, if biomass markets were available, a silvicultural liberation cut might be profitable as the first step toward stand rehabilitation. For example, a 100% measurement and evaluation of all residual stems (≥ 11.4 cm)in one 4 ha stand indicated that a complete removal harvest would produce a total of 111,561 kg of biomass. If the residual stems were merchandised by size and value, then 93 cubic meters of sawlogs and 52,171 kg of biomass (wood chips) were available.
