Theses and Dissertations Collection

Land managers have been using mechanical treatments to reduce fuels in ponderosa pine (Pinus ponderosa) forests to mitigate high severity fire effects. Before the 2007 Egley Fire Complex, mechanical thinning, slash and pile burns, and understory burns were implemented as fuel reduction treatments in the dry ponderosa pine-dominated Malheur National Forest in eastern Oregon. To compare post-fire vegetation recovery between mechanical treatments and untreated control areas, 35 treated and untreated paired plots were sampled in 2016. Sites were stratified by elevation, aspect, and the remotely sensed burn severity gradient represented by the delta Normalized Burn Ratio (dNBR). Post-fire vegetation recovery was assessed at the 35 paired field sites by measuring tree density, seedling regeneration, understory plant response, and fuel loads. The intent of this study was to document to what extent tree density, seedling regeneration, understory plant community composition, and fuels change across the burn severity gradient and to quantify to what extent pre-fire fuel treatments affect burn severity and long term (9 years) vegetation recovery. Estimated site recovery time and other implications for management of dry coniferous forests are discussed.