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Assessing the effectiveness of seeding and fertilization treatments for reducing erosion potential following severe wildfires

Informally Refereed

Abstract

Postfire slope stabilization treatments are often prescribed following high‑severity wildfires on public lands to reduce erosion, maintain soil productivity, protect water quality, and reduce risks to human life and property. However, the effectiveness of slope stabilization treatments remains in question. For this study, tests were on effectiveness of seeding and fertilization treatments for increasing total live plant cover and reducing percent bare soil during the first 2 years following wildfire in dry mixed-conifer forests of north-central Washington State. Assessments were made on the effects of four seeding treatments (none, two perennial species mixes, and a winter wheat monoculture) and three fertilization levels (0, 50, and 100 lb N/acre) in factorial combination on percent bare ground, and plant cover using a generalized randomized complete block design at eight sites. Half of the sites also received aerially applied straw mulch. Surveys of vegetation responses during the first two summers following fire showed that seeding, fertilizing, and straw mulching all significantly influenced bare ground and/or live plant cover. Fertilizing alone increased mean live plant cover by 4 to 9 percent in 2005, and by 8 to 12 percent in 2006. Seeding alone increased mean live plant cover by only 1 to 2 percent in 2005 and 0 to 3 percent in 2006. Fertilizing and seeding together increased plant cover by up to 11 percent in 2005 and 20 percent in 2006 and reduced bare ground by up to 13 percent in 2005 and by 21 percent in 2006. Of the seeded species, two native perennial forbs, yarrow (Achillea millifolium) and fireweed (Chamerion angustifolium), contributed the most to total plant cover. Straw mulching increased litter cover by 10 to15 percent, but had little effect on live plant cover. Our results suggest that fertilization treatments can increase the effectiveness of seeding treatments and stimulate regrowth of surviving native vegetation following wildfires, particularly in forest types with understory vegetation dominated by species that resprout following fire. More work is needed to determine appropriate levels of fertilization and to better identify species and environmental factors that produce better results for seeding treatments.

Parent Publication

Keywords

wildland fire management, postfire slope stabilization treatments, seeding, fertilization, erosion

Citation

Peterson, David W.; Dodson, Erich K.; Harrod, Richy J. 2007. Assessing the effectiveness of seeding and fertilization treatments for reducing erosion potential following severe wildfires. In: Butler, Bret W.; Cook, Wayne, comps. The fire environment--innovations, management, and policy; conference proceedings. 26-30 March 2007; Destin, FL. Proceedings RMRS-P-46CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. CD-ROM. p. 465-474
https://www.fs.usda.gov/research/treesearch/28591