Abstract:
T he 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
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 postsettlement
woodland expansion are not always
clear or consistent across sites and have led to
debate and legal challenges over control projects and
management plans for western juniper.
This publication represents a synthesis of what
is known about the history, biology, ecology, and
management of western juniper. Western juniper
occupies 9 million acres in central and eastern
Oregon, northeastern California, southwestern
Idaho, and northwestern Nevada, and occurs in
a few outlying stands in southern Washington.
Presettlement changes in woodland abundance
and distribution are largely attributed to long-term
changes in temperature, amounts and distribution
of precipitation, and the extent and return intervals
of fire. Evidence supporting rapid post-settlement
expansion is derived from old surveys, photographs,
the distribution of relict presettlement woodlands,
and tree-ring chronologies.
