A pandora moth (Coloradia pandora Blake) outbreak began in 1991 in a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) spacing study area that also included scattered sugar pine (P. lambertiana Dougl). The relation of defoliation to five tree spacings (with and without understory vegetation) was examined, and stand growth reduction...
Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa and lodgepole pine stands in central Oregon. Basal area growth was modeled as a function of other stand and tree variables to address five general objectives: 1) to compare the predictive ability of distance-dependent versus distance-independent stand...
This thesis examines the 8-year growth trend of
Douglas-fir (Pseudotsuga menziesii (mirb.)Franco), ponderosa
pine (Pinus ponderosa Dougl. ex laws.), and whiteleaf
manzanita (Arctostaphylos viscida Parry). Manzanita stands
ranging from 1700/ha to 27000/ha density were grown among
mixed conifers of the same age, which were planted in 1981
at 250x250 cm...
Vegetation patterns and species distributions are strongly linked to soil moisture regimes, and populations within a species from contrasting climatic regimes could exhibit differences in the degree to which certain functional traits related to establishment are expressed. Tree seedling survival is crucial for forest regeneration, and thus may be a...
Northeastern Oregon geology and climate provides moderately productive conditions for forest management and timber production. Although site preparation and planting are commonly used silvicultural practices, little research exists on the efficacy of specific forest herbicides and responses of seedling survival and growth in this region. This research seeks to improve...
Juvenile Douglas-fir, ponderosa pine, and whiteleaf manzanita
growth in southwest Oregon varied with density of co-developing
manzanita and presence of herbaceous cover. Plant xylem pressure
potential and stomatal conductance of each species was responsive
to competition-induced depletion of soil water. Rates varied among
species. The best correlations with growth usually...
The dynamics of stands In old-growth ponderosa pine (Pinus
ponderosa) forests on the eastern flank of the central Oregon
Cascades are Investigated. Age structure and spatial pattern of
ponderosa pine within the Pringle Falls Experimental Forest
Research Natural Area coupled with the fire history of the area
aid In Interpreting...
This research assessed the effect of western juniper (Junlperus
occldentalls) removal on understory plant production and cover and
ponderosa pine (Pinus ponderosa) growth and plant water status.
A complete randomized block design, with four blocks and four
treatments was established in the summer of 1984 near Prineville,
Oregon. The four...
Geographic variation was investigated among 225 locations from five geographically disjunct regions in central Oregon. Characters included: germination speed and uniformity in two test environments
differing in stratification period and incubation temperature; weight, three dimensions and three 'angles' of seeds; weight and three dimensions of wings; cone length and scale...
Forest species classifications are becoming increasingly automated as advances are made in machine learning. The algorithms used to identify tree species range from simple decision trees to intricate neural networks, and often excel in accurately delineating tree species. However, complex algorithms can have high input costs, including the cost of...
The population genetic structure of ponderosa pine (Pinus ponderosa Dougi.) in the Willamette Valley of Oregon was investigated. Cones were collected from native stands of ponderosa pine from the Willamette Valley, eastern Oregon, southwest Oregon and the Puget Sound Basin of Washington. Seeds were subjected to isozyme analysis of 12...
Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis var. occidentalis Hook.) encroachment has been previously documented in the sagebrush steppe and upper elevation aspen communities. While these vegetation changes and dynamics have...
The Metolius Research Natural Area (RNA), located 29 km northwest of Sisters, Oregon, was originally established in 1931 to maintain a ponderosa pine (Pinus ponderosa Dougl. Ex Laws) and dry, mixed-conifer forest with the aim to meet objectives of preserving natural conditions, providing for research opportunities, and preserving gene pools...
The effects of prescribed burning on the rates of recent litter
decomposition, nitrogen and phosphorus release from litter, soil total and
inorganic nitrogen pools, and net nitrogen mineralization were determined in
ponderosa pine sites that had been burned 0.3, 5 or 12 years earlier. Prescribed
burning decreased litter decomposition rates...
Tree growth and soil nutrient responses to prescribed underburning were determined for a period of up to 12 years at four sites in northcentral and central Oregon ponderosa pine stands (Pinus ponderosa Dougl. ex Laws).
Differences reported are significant at a = 0.10. During the first 4-growing-season-measurement period after
underburning,...
Planting techniques, size and age of seedlings, and protection
against animals were investigated for their influence on survival of
ponderosa pine at two sites in southern Oregon. Caging and mulching
with paper were the most effective measures for reducing mortality.
Preliminary trials prior to large-scale planting were recommended for
determining...
The effects of six alternative site preparation
treatments were compared at three different sites in
southcentral Oregon. Treatments included a logged-only
control, ripping, brushblading, disking, chemical, and
chemical followed by disking. Subplots containing
ponderosa pine bareroot (2+0) and containerized (1+0)
and lodgepole pine containerized (1+0) seedlings were
also included in...
The objective of this project was to investigate the fate of ponderosa pine regeneration from seed to established seedling, and to determine the relative influences of several important stand elements on those fates. The project was carried out in a series of observational and experimental recruitment studies in central Oregon....
The relationship between annual foliage production and nitrogen and water stress was examined in 14 naturally regenerated, mid-rotation ponderosa pine stands in central Oregon. Current-year and older foliage masses, and foliage nitrogen contents and concentration were estimated from 132 destructively sampled trees. Litterfall mass and nitrogen retranslocation rates from senescing...
Knowledge of stand structure, stand dynamics, and production ecology of species mixtures lags well behind that of single-species, even-aged stands. Two mixed-species spacing trials in central Oregon allowed investigation of mixed-species dynamics in a controlled experimental setting. The first site, Pringle Butte, is a mixture of ponderosa pine (Pinus ponderosa...
The survival, growth, foliar nutrient status, ectomycorrhiza (EM) colonization,
and associative N-fixation of ponderosa pine seedlings (Pinus ponderosa var. ponderosa
Doug!. ex Laws.) were studied under different gap sizes in forest canopy during the first growing season. Seedling performance variables were assessed relative to gap size of the forest canopy...
The study was conducted over approximately 191,000 acres in central Klamath County, Oregon. The research had three objectives: first, to describe and classify the seral and near-climax vegetation by using polyclimax principles; secondly, to determine the southern extension of five plant associations and one plant associes as previously described by...
This study explored the relationship of mature ponderosa pine (Pinus ponderosa Dougl. ex Laws) tree vigor and competitive zone density following thinning and fuel reduction treatments. Competitive zone density (CZD) was defined as the total tree basal area (m²/ha) surrounding a given ponderosa pine tree within a 10m fixed radius...
Without the natural occurrence of fire in ponderosa pine forests of the western US, lodgepole pine has started to dominate regeneration in many forest stands and may be gradually replacing ponderosa pine over time. This development, however, conflicts with recent efforts in this region to restore old-aged, open ponderosa pine...
Regression equations for estimating the aboveground biomass (ovendry weight) of individual plants of 10 shrub and 2 pine species were developed from data collected in south central Oregon. All include a single independent variable and were generated from logarithmically transformed data. Total aboveground biomass of each shrub species is predicted...
The state of Oregon has two distinct climate types bisected by the crest of the Cascade Mountain range. The western side of the Cascades experiences high levels of precipitation and mild temperatures due to the maritime influence of the Pacific Ocean, while the eastern side lies in the rain shadow...
Ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta var. murrayana) forests of south-central Oregon have been extensively researched over the last century. However, little information has been reported on overstory composition and stand structure shifts associated with fire exclusion within inter-mixed ponderosa pine and lodgepole pine stands of the...
The objective of this research was to determine which
environmental resources, light, water, and nutrients,
control understory plant production and composition in a
Pinus ponderosa forest in northeastern Oregon. A split-plot
experimental design, with three blocks, four
treatments, and 44 plots, was established in the summer of
1985. Twenty plots...
Although previous research in central Oregon has shown soil compaction can lead to a decline in site productivity, the subject is not understood well enough to predict the growth changes resulting from a given level of soil compaction. A study was initiated to relate the basal area, height and volume...
Fire has played a prominent role in the development and character of the ponderosa pine forests in western North American. Its
records are written in the scars of trees that have survived the fire.
Careful studies of these fire-scars may be used as a means of reconstructing
the fire history...
Infestations of the western pine shoot borer (Eucosma sonomana Kearfott) in young stands of ponderosa pine (Pinusponderosa Lawson), were surveyed on the Deschutes National Forest. Elevation, slope, aspect, tree height, tree diameter, number of shoots in the terminal whorl, stand density, stand age and plant association for each stand were...
Water treatments were applied to young ponderosa pine trees in the Eastern Cascades, Oregon during the 2003 growing season, and shade treatments were applied during the 2003 and 2004 growing seasons to understand how photosynthesis and soil respiration, particularly the root/rhizosphere fraction (R[subscript rrh]), would respond to increased moisture availability...
Relatively recent increases in ponderosa pine abundance have effected unprecedented changes to ecosystem structure and function. Efforts to restore ponderosa pine systems are often focused on the manipulation of tree structure and the re-introduction of a more natural fire regime. Successful restoration should also incorporate understory components but information addressing...
The pine butterfly (Neophasia menapia C. Felder & R. Felder) (Lepidoptera: Pieridae) is a relatively host-specific defoliator of ponderosa pine (Pinus ponderosa Dougl. ex Laws). From 2008 to 2012, the Malheur National Forest was subject to an outbreak of pine butterfly in ponderosa pine, peaking at ~100,000 ha of forest...
Published February 1992. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Fuel accumulation and climate shifts are predicted to increase the frequency of high-severity fires in ponderosa pine (Pinus ponderosa Dougl. ex Laws) forests of central Oregon. The combustion of fuels containing large downed wood can result in intense soil heating, alteration of soil properties, and mortality of microbes. Previous studies...
Mammal and bird damage recorded on Douglas-fir and ponderosa pine plots-randomly established in Oregon and Washington during 1963-64, then observed for 5 to 10 years-was evaluated for impact on survival and growth. In all, 194 plots were installed, and 10 of the 110 seedlings on each plot were caged to...
Regression models of height growth and survival were fitted to aggregate data for trees, protected and not protected from animal damage, that had been surveyed on Douglas-fir and ponderosa pine plantations in Oregon and Washington. Animal damage significantly affected both height and survival. Dynamic programming analysis-using both soil expectation (Se)...