Post-harvest assessment of downed woody debris and nutrient distribution following conventional pulpwood and wood pellet feedstock harvests in the southeastern US

https://doi.org/10.1016/j.jenvman.2025.125719

Journal of Environmental Management June 2025

Authors
Hannah C.M. Bays, University of Georgia, Harley Langdale Jr. Center for Forest Business
M. Chad Bolding, University of Georgia, Harley Langdale Jr. Center for Forest Business
Joseph L. Conrad IV, University of Georgia, Harley Langdale Jr. Center for Forest Business
Holly L. Munro, NCASI
Scott M. Barrett, Department of Forest Resources and Environmental Conservation, Virginia Tech

Abstract
Wood pellets are an important fuel for bioenergy production, with demand expected to increase as renewable energy production expands globally. Common feedstock sources include in-woods chips or pulpwood-sized roundwood harvested from both thinnings and final harvests in pine (Pinus spp.) stands. Wood pellet production may result in more intensive harvesting and less downed woody debris (DWD) retained post-harvest, which could affect site sustainability. To examine this, we conducted a field-based study comparing the retention and distribution of DWD material across wood pellet and conventional pulpwood harvests (n = 75). Wood pellet clearcuts had lower coarse and fine DWD for total treatment area (P = 0.06) and a reduction in fine DWD on landings (P = 0.06) compared to conventional harvests. Additionally, operations incorporating in-woods chipping for pellet feedstock decreased coarse DWD in clearcut harvest areas by 2.74 Mg ha−1 compared to conventional harvesting sites (P = 0.05). Conversely, thinning treatments showed no significant differences in DWD retention on landings (P = 0.40), harvest areas (P = 0.79), or total area (P = 0.61). Pellet harvests with in-woods chipping reduced DWD nutrient retention, particularly fine and coarse debris carbon content on landings (P = 0.02), and fine debris nitrogen content in harvest areas (P = 0.07). Our study suggests that wood pellet clearcut harvests using in-woods chipping reduces DWD. However, remaining amounts are within acceptable ranges suggested by Biomass Harvesting Guidelines (BHGs). Findings suggest a need for complementary research in the southeastern US to assess threshold levels of DWD required for maintaining site sustainability, water quality, and wildlife habitat.

Keywords: Forest residue, Coastal plain, Residue, Sustainability, Nutrient retention, Biomass, Forest management