Whole tree excavation of 41 western juniper (Juniperus
occidentalis Hook.), ranging in age from 2 to 34 years old,
was used to assess the development and structure of root
systems, to determine biomass allocation patterns, and to
develop mathematical relationships for estimating biomass
and root system dimensions in seedling and...
Western juniper is a native species in eastern Oregon that became invasive during the last century since its range increased fivefold from 1936 to 1988. Western juniper’s ability to absorb rainfall and groundwater has deleterious effects on stream flow and sensitive sage grouse habitat in eastern Oregon. New methods of...
The 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...
Patterns and costs of root/shoot allocations, response to reductions of above and below-ground tissue and to fertilization with nitrate and ammonium, and seasonal courses of physiological processes were measured on juvenile, small-adult, and large-adult Juniperus occidentalis growing in the field under ambient
environmental conditions in eastern Oregon.
Adult foliage had...
Understory species associations and their association with tree species were examined on three intensively studied stands. We studied the chronosequence of understory species associated with different aged singleleaf pinyon (Pinus monophylla Torr. and Frem.) trees. Mid- to late pinyon-juniper understory succession was found to be more spatial than floristic in...
Evidence suggests that western juniper
(Juniperus occidentalis) in Central Oregon affects
understory production and composition. As trees
increase in size and density, understory production is
reduced and composition changes. This study was
designed to identify the relationship between
production and composition of understory vegetation
and various tree canopy sizes of...
Understanding the effects of disturbance and restoration on a species’ habitat is essential for understanding the demographic rates and population trends observed in a species. Sufficient habitat provides the space and resources required for survival and successful reproduction, such as food availability, access to water, protection from predators, protection from...
Knowledge of old-growth Juniperus occidentalis woodlands, which occur in central and eastern Oregon, is limited. Wise management of these woodlands necessitates a better understanding of the community ecology. The community structure of woodlands at seven sites in three areas of central Oregon was studied. Measurements taken at nine plots per...
The expansion of native, woody plants is a global phenomenon with characteristics and effects that are often indistinguishable from exotic invasions. These expansions have largely been driven by altered fire regimes and favorable climatic conditions. In the Great Basin of western North America, expansion of conifers such as western juniper...
The heartwood of mesquite (Prosopis juliflora var. velutina) and of Utah juniper (Juniperus utahensis) is generally considered to have outstanding decay resistance. Quantitative evidence of the juniper superiority appears in a study of old fence lines by Meagher. Nearly three fourths of the juniper posts averaging 3.6 inches in diameter...
Logging and forest thinning operations generate large amounts of residues in the form of small trees, branches and foliage that are usually left on the ground to decay or are burned. These resources are readily available, but it is uneconomical to remove them from the forest. The potential utilization of...
Paired 30-day trials were conducted to evaluate
Agropyron spicatum germination when treated with two
concentrations of throughfall leachates from western
juniper slash in two stages of decomposition. Data from
a second pair of 49-day greenhouse trials were analyzed
to evaluate emergence and growth of Aqropyron spicatum,
Oryzopsis hymenoides, and Poa...