Forest management effects on downed dead wood at stand and landscape scales in a temperate forest of the central United States

Abstract

Downed dead wood (DDW) is a critical component of forest ecosystems, with DDW dynamics largely affected by rates of input from standing trees to the forest floor and loss through decomposition or removal. Forest management decisions affect DDW dynamics based on the type of silvicultural harvest applied at the stand level and the administration of those treatments across the landscape. The Missouri Ozark Forest Ecosystem Project (MOFEP) is a landscape-scale experiment that tests the effects of three forest management treatments, even-aged management (EAM), uneven-aged management (UAM), and no harvest management (NHM), on forest ecosystems in the Ozark Highlands region of Missouri. In this study, we evaluate the effects of stand-level silvicultural treatments (clearcutting and intermediate thinning in EAM; single-tree selection and group selection in UAM) and landscape-level forest management treatments (EAM, UAM, and NHM) on the volume of DDW and distribution across decay classes over a 21-year period. At the stand level, clearcutting resulted in the greatest short-term increase in DDW volume among the silvicultural treatments. Following harvest, the DDW was primarily within the undecayed classes during the first few years after harvest but shifted to the greater decay classes during the second decade after harvest. At the landscape level, the forest management treatments did not differ in total DDW volume through time, although EAM and UAM had greater amounts of undecayed DDW than NHM shortly after harvest. Across all treatments, the volume of DDW increased through time, likely due to effects of the forest management but also due to background tree mortality related to oak decline during the study period. Overall, our results show differences in effects of stand-level silvicultural treatments on DDW dynamics and highlight the need to consider both stand-level and landscape-level effects of forest management systems in decision making.