Salvage-logging and artificial seeding of grass following wildfire are common practices in coniferous forests of the western United States, yet few studies have
quantified the ecological effects of these post-fire activities. The effects of post-wildfire salvage-logging and grass-seeding on vegetation composition, aboveground biomass, and growth and survival of Pinus ponderosa...
Our objectives were to determine 1) the concentration of prostaglandin
F2α (PGF2α) in whole and extended bovine semen, 2) if concentrations of
prostaglandins in extended bovine semen are correlated to fertility, and 3) if PGF2α
administered at the time of artificial insemination would improve conception rate.
Concentration of PGF2α tended...
The objective of this study was to evaluate the influence of cow age on grazing distribution relative to mountain riparian areas. In each of two years, sixty cow-calf pairs were stratified by age into the following treatments: 1) thirty first calf heifers (442 kg, body condition score (BCS)=4.5), and 2)...
The effects of natural preconditioning (source wood), wood species, and previous
exposure of wood to two types of fungi on the feeding rates and protozoa survival in the
Pacific dampwood termite Zootermopsis angusticollis (Isoptera: Termospidae) were
examined under laboratory conditions. Termites were exposed to four wood species that
had been...
The host preferences and wood channelization rates of
scolytid and cerambycid beetles were studied at the H. J.
Andrews Experimental Forest (Lane County, Oregon) during
1986 and 1987. Attack density and gallery volumes were
measured in fall-felled experimental logs of four major
conifer species: Douglas-fir (Pseudotsuga mensiesii (Mirb.)
Franco), western...
The structuring of canopy arthropod communities was reviewed and investigated in relation to tree species diversity and its component factors, interspersion of different species and density of each tree species. Fifteen treatments of Douglas-fir (Pseudotsuga menziesii) and red alder (Alnus rubra) (various densities and proportions of each) were randomly assigned...
The impact of various factors on seed production in a
Douglas-fir (Pseudotsuga menziesii) seed orchard in
western Oregon was examined by monitoring the fate of
seeds in thirty cones, stratified into three crown levels,
on each of ten trees during the 1984 growing season.
Cones were examined monthly between April...
The role of insect herbivores in the nutrient cycling dynamics of forest ecosystems remains poorly understood. Although past research in herbivory has focused primarily on the deleterious effects that insects can have on tree growth and mortality, the overall effects of herbivory are more complex. Herbivores have the potential to...
A portion of this study was initiated to provide the
basis for implementing a chill unit accumulation procedure
in Yemen. Most continuous or daily minimum, maximum
temperature models severely underestimated chilling units,
and slight modifications offered little improvement for the
complex models. Only the Crossa Raynaud formula approximated
generally accepted...
Invasion by non-native plants into natural areas is an important component of global change that threatens biodiversity and ecosystem structure and function. Mountains are currently among the least invaded ecosystems, however, these biodiversity hotspots are increasingly under threat of exotic plant invasion. Evaluation of plant species distribution patterns in mountain...