A JFSP Fire Science Exchange Network
Bringing People Together & Sharing Knowledge in the Northern Rockies

Influence of wildland fire along a successional gradient in sagebrush steppe and western juniper woodlands

Author(s): Eva K. Strand, Stephen C. Bunting, Robert F. Keefe
Year Published: 2013

Western juniper (Juniperus occidentalis Hook. var. occidentalis) has been expanding into sagebrush (Artemisia L. spp.) steppe over the past 130 years in Idaho, Oregon, and California. Fuel characteristics and expected fire behavior and effects change as sagebrush steppe transitions into juniper woodlands. Little is currently known about how wildfire influences burn severity and ecosystem response in steppe altered by woodland conversion. In 2007, the Tongue-Crutcher Wildland Fire burned 18,890 ha along a successional gradient ranging from sagebrush steppe to mature juniper woodlands, providing a unique opportunity to evaluate the effects of prefire vegetation on burn severity and ecosystem response across spatial scales. Plot-scale burn severity was evaluated with the composite burn index (CBI) in locations where prefire vegetation data were available, and landscape-scale burn severity was estimated via remotely sensed indices (differenced normalized burn ratio [dNBR] and relative differenced normalized burn ratio [RdNBR]). Strong positive relationships exist between CBI and remotely sensed burn severity indices in woodlands, whereas the relationships are weaker in steppe vegetation. Woodlands in late structural development phases, and sagebrush patches near developed woodlands, incurred higher burn severity than steppe and young woodlands. The results support the idea that a threshold exists for when juniper-encroached sagebrush steppe becomes difficult to restore. Implications for fire management in sagebrush/juniper ecosystems are discussed.

Citation: Strand, Eva K.; Bunting, Stephen C.; Keefe, Robert F. 2013. Influence of wildland fire along a successional gradient in sagebrush steppe and western juniper woodlands. Rangeland Ecology & Management. 66(6): 667-679.
Topic(s): Fire Effects, Ecological - First Order, Fire Intensity / Burn Severity, Fire Regime
Ecosystem(s): Aspen woodland, Mountain shrubland/wooded draw, Juniper woodland, Sagebrush steppe
Document Type: Book or Chapter or Journal Article
NRFSN number: 12149
FRAMES RCS number: 16297
Record updated: May 10, 2018