Paper addresses rodent responses to woody biomass harvesting

Increased interest in renewable energy sources could lead to greater use of logging or harvest residues for bioenergy production. Because many forests in the southeastern US are intensively managed, the region is likely to be an important producer of bioenergy feedstocks. However, reductions of downed wood via woody biomass harvests could affect forest ecosystems and wildlife communities.

Rodents are an important component of the biological community that could be affected by woody biomass harvests. They serve critical roles in forest ecosystem function, such as seed dissemination and herbivory, and are predators of and prey for many species. Furthermore, rodents often use downed woody debris and other structural cover to meet numerous life-history needs.

Recently, scientists with North Carolina State University, the University of Georgia, and Weyerhaeuser Company published a paper in the Journal of Wildlife Management addressing rodent responses to woody biomass harvesting. The investigators experimentally retained different volumes of woody debris in clumped and dispersed patterns following clearcut harvesting in intensively managed loblolly pine forests in North Carolina and Georgia.

The authors conclude that their results “suggest rodents are not sensitive to current levels of woody biomass harvests in southeastern United States pine plantations.” The abstract for the paper follows.

“Harvest of low value trees and logging residues for bioenergy reduces downed wood post-harvest with potential indirect negative effects on ground-dwelling wildlife such as rodents. We assessed the influence of woody biomass harvests on rodent abundances using an operational-scale, randomized complete block experimental design study in North Carolina (4 blocks) and Georgia, USA (4 blocks). Each block contained 6 treatments randomly applied to a clearcut harvest, that varied by volume of woody biomass retained, and that represented existing woody biomass harvest recommendations. We livetrapped rodents in 2011–2013, calculated the minimum number known alive for each captured species, and used the value as an index of abundance. We compared abundance of the 3 most commonly captured species (deer mice [Peromyscus spp.], house mouse [Mus musculus], and hispid cotton rat [Sigmodon hispidus]) among treatments with generalized linear mixed effects models. We assessed relationships among species’ abundance and measurements of downed woody debris and vegetation in each treatment unit using linear regression. Although abundance varied among treatments in some cases, we did not detect consistent relationships between woody biomass retention treatments and abundance. Volume of downed woody debris in the treatment unit negatively influenced house mice but had varying influences on deer mice across years. Downed woody debris groundcover negatively affected deer mice in North Carolina in 2012. Litter groundcover negatively influenced deer mice and hispid cotton rats, whereas grass groundcover positively influenced the hispid cotton rat. The lack of consistent relationships between rodent abundance and volume of retained woody debris suggests that the rodent species captured in this study were not affected by current efficiencies of operational woody biomass harvests in southeastern United States loblolly pine (Pinus taeda) plantations. However, focal species were habitat generalists and less common species may have greater sensitivity to biomass harvests.”

This is one of several papers to emerge from a study in which NCASI collaborated and that has also addressed responses of shrews, herpetofauna, wintering birds, breeding birds, and invertebrates to woody biomass harvesting. In this most recent paper, Fritts and her co-authors report that “this study [of rodents] adds to the growing body of research indicating that wildlife in southeastern pine plantations generally are not influenced by harvest of low-value trees or other logging residue for bioenergy.”  


Fritts, S.R., C.E. Moorman, S.M. Grodsky, D.W. Hazel, J.A. Homyack, C.B. Farrell, S.B. Castleberry, E.H. Evans, and D.U. Greene. 2017. Rodent response to harvesting woody biomass for bioenergy production. Journal of Wildlife Management 81: 1170–1178.