Biology, ecology, and management of western juniper (Juniperus occidentalis)

Published June 2005. Reviewed July 2017. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalogThe rapid expansion of western juniper into neighboring plant communities during the past 130 years has caused considerable concern because of increased soil erosion, reduced stream\ud flows; reduced forage production; altered wildlife habitat; changes in plant community composition, structure, and biodiversity; and the replacement of mesic and semi-arid plant communities with woodlands. However, the impacts of post settlement woodland expansion are not always clear or consistent across sites and have led to debate and legal challenges over control projects and\ud management plans for western juniper.\ud This publication represents a synthesis of what\ud is known about the history, biology, ecology, and\ud management of western juniper. Western juniper\ud occupies 9 million acres in central and eastern\ud Oregon, northeastern California, southwestern\ud Idaho, and northwestern Nevada, and occurs in\ud a few outlying stands in southern Washington.\ud Presettlement changes in woodland abundance\ud and distribution are largely attributed to long-term\ud changes in temperature, amounts and distribution\ud of precipitation, and the extent and return intervals\ud of fire. Evidence supporting rapid post-settlement\ud expansion is derived from old surveys, photographs,\ud the distribution of relict presettlement woodlands,\ud and tree-ring chronologies