Drought resistance among genotypes of Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murr.) Pan., Cupressaceae) seedlings was evaluated both in the field and in the greenhouse. Field water potentials (Ψ) of 5-year-old seedlings were measured at two high-elevation plantation sites where summer drought occurs. Measurements of Ψ were compared to survival two years...
A physio-ecological study of Lobaria pulmonaria (L. ) Hoffm.
was done to determine if geographic variation occurred within the
species. Lobaria pulmonaria was collected from Table Mountain,
Oak Creek, and Lost Prairie, located in the Coast Range, Willamette
Valley, and Cascade Range respectively in Western Oregon.
During 1971 and 1972...
This study describes the soils, vegetation and age structure
of the Pinus contorta forests of Crater Lake National Park. Growth
rates of P. contorta, and levels of infection and impact of dwarf
mistletoe (Arceuthobium americanu1r) on growth of P. contorta
individuals are compared among communities.
Vegetation description is based on...
Twelve plots at six sites in southwestern Oregon were studied to determine the degree to which various soil characteristics are related to the occurrence and growth of Chamaecyparis lawsoniana and Thuja plicata. Soil profiles and vegetation were described in each plot, and measurements were made of insolation, soil and litter...
Seedlings from 25 provenances of Abies grandis and Abies
concolor were studied at two plantations, 12 at Philomath, Oregon,
and 13 at Camino, California. Native seedlings were studied at four
of the provenances' field sites. Stomatal infiltration pressure
measurements and plant moisture stress measurements were made
throughout one summer on...
The effects of burial by tephra (volcanic aerial ejecta) on
forest understory plants were examined northeast of Mount St. Helens,
Washington, in the area where the 18 May 1980 eruption deposited
tephra but did not destroy canopy trees. At six sites along a tephra
depth gradient from 2-15 cm, understory...
This study examines several aspects of nitrogen fixation by
Purshia tridentata (Pursh) D. C., a rosaceous shrub widespread in the
central Oregon pumice region, especially as an understory species in
Pinus ponderosa and Pinus contorta forests. Anatomical studies of
root nodules under the light microscope revealed strong similarities
to other...