|Miller, Rick - OREGON STATE UNIVERSITY|
|Rose, Jeff - OREGON STATE UNIVERSITY|
Submitted to: Ecology and Management of Pinyon Juniper Communities Within The Interior W
Publication Type: Proceedings
Publication Acceptance Date: January 12, 1998
Publication Date: N/A
Interpretive Summary: Western juniper has been expanding into sagebrush/bunchgrass rangeland for the past 100 years. The expansion of western juniper is primarily a result of reduced fire intervals on sagebrush/bunchgrass since settlement. During the advanced stages of juniper encroachment, the rangeland looses much of its potential to produce forage for both livestock and wildlife, and the erosion hazard of the site may increase. Previous research has demonstrated that forage production may be reduced up to 90% by juniper encroachment. However, land managers have not had specific criteria to use in assessing potential impacts of western juniper invasion on different types of Great Basin rangeland. This research presents a discription of the stages of juniper invasion, and will help land managers make planning decisions for rangelands that are impacted by western juniper. A discription is provided for specific thresholds of invasion after which juniper control will be labor-intensive and/or costly.
Technical Abstract: Juniper woodlands are frequently treated generically in management, wildlife studies, and environmental issues. Western juniper grows on a broad variety of soils and terrain, creating a high degree of spatial variability in stand structure and function. Stand heterogeneity can also be attributed to temporal or successional differences in shrub steppe conversion to juniper woodlands. During conversion a threshold is crossed which moves the shrub steppe community to a new steady state driven by different ecological processes. It is important to recognize both spatial and temporal heterogeneity when evaluating habitat suitability, predicting potential resource problems related to stand development, developing management plans, and setting priorities.