Battaglia, M.A., C. Rhoades, P. Fornwalt, and M. Rocca. 2015. Mastication effects on fuels, plants, and soils in four western U.S. ecosystems: Trends with time-since-treatment. Joint Fire Science Final Report, Project 10-1-01-10. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO. 37 pp.
Mechanical fuel reduction mulching treatments have been implemented on millions of hectares of western North American forests in recent years. Mulching transfers woody biomass to the soil surface, creating a treatment with no ecological analogue. This relatively-new management practice may have lasting effects on forest regeneration, understory plant communities, fuel loads, and ecosystems nitrogen dynamics and forest productivity.
This project compared fuel reduction mulching and adjacent untreated stands at conifer ecosystems distributed across Colorado and evaluated the effects of mulch depth both experimentally and in operational units. Results from this study provide land managers and researchers greater understanding of the lasting effects of mulching on community and ecosystem processes, including higher fuel loads and increased soil moisture. Mulching did not significantly effect soil nitrogen, and seedling regeneration was observed even with mulch depths of 15 cm.