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ARS Home » Pacific West Area » Burns, Oregon » Range and Meadow Forage Management Research » Research » Publications at this Location » Publication #298068
Title: Vegetation recovery and fuel reduction after seasonal burning of western juniper

Author
item Bates, Jonathan - Jon
item O'CONNOR, RORY - Brigham Young University
item Davies, Kirk

Submitted to: Fire Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2014
Publication Date: 9/29/2014
Publication URL: http://handle.nal.usda.gov/10113/60077
Citation: Bates, J.D., O'Connor, R., Davies, K.W. 2014. Vegetation recovery and fuel reduction after seasonal burning of western juniper. Fire Ecology. 10(3):27-48. doi: 10.4996/fireecology.1003027.

Interpretive Summary: The decrease in fire disturbance has been recognized as a main cause of a nearly 10-fold piñon- juniper in the western United States since the late 1800’s. Woodland control measures using chainsaws, heavy equipment and prescribed fire are used to restore sagebrush steppe plant communities. We compared vegetation recovery following cutting and prescribed fire treatments on three western juniper) woodland sites in southeast Oregon; comparisons including untreated controls, partial cutting followed by fall broadcast burning (SEP), clear-cut and leave (CUT), and clear cut and burned in early winter (JAN), late winter (MAR), and spring (APR). Five years after treatment perennial bunchgrasses dominated two sites and co-dominated with invasive annual grasses at one site. Except for Sandberg’s bluegrass (Poa secunda Vasey), other herbaceous lifeforms increased at all three site treatments and were greater than woodland controls. The results demonstrate piñon-juniper treatments are needed to maintain sagebrush steppe communities for dependent wildlife species, biological diversity, and sustaining grazing values.

Technical Abstract: The decrease in fire disturbance has been recognized as a main cause of expansion of North American woodlands. Pinus-Juniperus L. (Piñon- juniper) in the western United States have expanded in area nearly 10-fold since the late 1800’s. Woodland control measures using chainsaws, heavy equipment and prescribed fire are used to restore sagebrush steppe plant communities. We compared vegetation recovery following cutting and prescribed fire treatments on three sites in late Phase 2 (mid succession) and Phase 3 (late succession) Juniperus occidentalis Hook. (western juniper) woodlands in southeast Oregon. Treatments were untreated controls, partial cutting followed by fall broadcast burning (SEP), clear-cut and leave (CUT), and clear cut and burned in early winter (JAN), late winter (MAR), and spring (APR). Cover and density of herbaceous, shrub, and tree layers were measured. Five years after treatment perennial bunchgrasses dominated two sites and co-dominated with invasive annual grasses at one site. Except for Sandberg’s bluegrass (Poa secunda Vasey), other herbaceous lifeforms increased at all three site treatments and were greater than woodland controls. For each site, shrub, herbaceous and ground cover response variables equalized or had started to converge among the treatments the 4th or 5th year following treatment applications. SEP and APR treatments were mostly effective at consuming fuel sizes up to and including 1000 hr. fuels while JAN and MAR treatments only consumed 1 and 10 hr. fuels. Winter burning treatments (JAN, MAR) and the CUT treatments did not kill small junipers and seedlings (<1.5m tall) and would require additional tree control measures for sites to fully recover to functional sagebrush-herbaceous plant communities. The results demonstrate piñon-juniper treatments are needed to maintain sagebrush steppe communities for dependent wildlife species, biological diversity, and sustaining grazing values.