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Vegetation Recovery and Fuel Reduction after Seasonal Burning of Western Juniper

Author:
Bates, Jonathan D., O'Connor, Rory, Davies, Kirk W.
Source:
Fire ecology 2014 v.10 no.3 pp. 27-48
ISSN:
1933-9747
Subject:
Artemisia, Juniperus occidentalis, Pinus, Poa secunda, autumn, biodiversity, chainsaws, clearcutting, control methods, cutting, fuels, fuels (fire ecology), grasses, grazing, herbaceous plants, pinyon-juniper, plant communities, prescribed burning, seedlings, shrubs, slash, spring, steppes, trees, wildlife, winter, woodlands, Oregon
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.
Agid:
60077
Handle:
10113/60077