Reduction of pocket gopher damage to conifer seedlings is important to successful reforestation in many regions of the Pacific
Northwest. The objective of this study was to determine the factors that influence the local distribution of the northern pocket gopher (Thomomys talpoides Richardson) in a forested region of south-central Oregon....
The capacity for root growth and concentration of indole-3-acetic acid and abscisic acid in the roots of western hemlock seedlings was investigated. The root regenerating capacity (RRC) was defined as the increase in root length, greater than 5 mm, following a 28-day test period. RRC measurements over a two-year period...
The objectives of this investigation were two-fold: (1) to examine possible seed and cone characteristics and their usefulness as seed maturity indices, and (2) to examine the effects of artificial ripening on seed maturation and germination. Cone fresh weight, cone length, cone specific gravity, cone color, seed fresh weight, seed...
Roots are considered to be the major production site of amino acids that appear in the xylem sap of conifers. The carbon skeleton of amino acids is derived from photosynthetically reduced carbon dioxide while the nitrogen is derived from the inorganic forms taken up by the roots. An experiment was...
The succession of plants over a period of 25 years was analyzed on clearcut areas in the western Cascades of Washington and Oregon. Thirty-three paired burned and unburned plots were reexamined in 1975. Data were combined with records from prior examinations by Morris (1970). Cover trends of six major brush...
Snags, standing dead trees, are used by many species of wildlife. Despite the importance of snags their basic ecology remains unknown.
Some forest management practices eliminate snags from the forest with a concomitant effect upon snag-dependent wildlife. My objective was to describe the density, spatial distribution, and physical character of...
The vegetation following forest site preparation was examined in ten clearcut units located in the western Oregon Coast Range. The site preparation techniques used in these units included scarification, slash burning, and chemical spraying. The ages of the clearcut units studied varied from one to nine growing seasons for the...
From a preliminary 1969 foliar analysis, eight provenances were chosen from the sixteen included in a region-wide, reciprocal Doulgas-fir provenance study for further study of variation in foliar nutrition. In the fall of 1969 separate foliar samples were collected from ten
trees per provenance at each of ten plantations ranging...
This study was divided into two parts. Part I was a quantitative description of some aspects of plant-water relations in Douglas-fir seedlings, and part II was tests of several techniques of screening selected families of Douglas-fir seedlings for drought resistance. Part I. During 20 mild summer days in 1976 at...
Foliage of Douglas-fir seedlings [Pseudotsuga menziesii (Mirb.) Franco] from two contrasting environments was sampled during progressive stages of two consecutive cycles of induced drought for leaf resistance, plant water potential , and abscisic acid content (ABA). One group of seedlings was placed in a controlled environment room while another group...
The relationship between ground vegetation and light intensity under a 60 to 65-year-old Douglas-fir forest was investigated. Biomass and height of ground vegetation were measured and cover was estimated on small sample units (30 centimeters in diameter) on permanent research plots, one-acre in size, on the George T. Gerlinger Experimental...
Oscilloscope display of modification of a square wave signal passed through stem tissue was evaluated as a means of detecting depth of dormancy and survival potential of coniferous seedlings. Trace form did not change during release from deep dormancy in Douglas fir. This release was judged by observing speed of...
The physiology of dormancy of western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings was examined. Many areas proved to exhibit similarities to those elucidated for Douglas-fir, although significant differences were also found and necessitate the use of caution in extrapolating data from one species to the other.. Dormancy of western hemlock...
Four brushfield reclamation methods were compared on a 28 hectare area supporting a dense overstory of red alder and a thick
understory of deciduous brush species. Tractor scarification, aerial application of 2, 4, 5-T and picloram followed by broadcast burning or tractor crushing, and aerial application of glyphosate were performed...
Pacific madrone, tanoak, and California black oak are the most economically promising native California hardwoods. Volume and value data indicate upward trends in growing stock levels and prices received for their products. These trends are likely to continue. They suggest research is particularly needed for: (1) seed fall and
regeneration,...
A survey of partial cuts planted with bare-root seedlings, was conducted on the Prospect Ranger District, Rogue River National Forest, Oregon, during the 1977 summer season. The purpose was to assess stocking and its composition under present levels of canopy cover, and to determine relationships between canopy density and performance...
Net photosynthesis was measured for photosynthetic light efficiency and capacity on two-year-old plants from eight different seed sources in three measurement periods. The measurement periods corresponded to the physiological periods 1) prior to bud swelling, 2) after needle elongation, and 3) predormancy. Measurement period differences in both photosynthetic efficiency and...
A detailed analysis was performed on the juvenile growth of six types of Douglas-fir stock under the influence of typical seral Coast Range vegetation. Objectives were to analyze competitive influences important to the growth of tree seedlings and evaluate differences between stock type characteristics and growth patterns in response to...
During the past 20 years, repeated thinning of a Douglas-fir forest, now 65 years old, has allowed desired limits of basal area to be maintained. In the process, the understory environment has altered sufficiently to allow Douglas-fir reproduction to establish in abundance. The forest is located on the east side...
The effects of winter plant moisture stress (P145) on bare-root 2+0 Douglas-fir (Pseudotsuga menziesii (Mirb.) Frañco) seedlings during nursery lifting and processing were studied. Seedlings were undercut at Ca. 4, 12, and 20 atm PMS during mid-February. Half of the seedlings undercut at 12 and 20 atm were not moistened...
The objectives of this investigation were to measure the seasonal and diurnal variations of starch as well as to relate these variations to growth of the trees. This study also microscopically examined the
needles to determine if starch exists in granular form in Douglas-fir. The objectives were designed to gain...
The need for increased efficiency in regeneration of western hemlock (Tsuga heterophylla (Raf.) Sarg.) requires greater understanding of seedling physiology. Experiments examined western hemlock seedling growth responses to in-bed root pruning, and pruning of shoots or roots prior to transplanting. Measurement of plant
moisture stress (PMS) after physical root disturbance,...
Noble fir (Abies procera Rehd.) is an upper elevation timber species native to the Cascade Range and (occasionally) the Coast Ranges of Washington and Oregon. It has always been a commerical species; however, recent changes in forest practices to increase harvests in the elevations where this tree occurs has caused...
Samples of mature vegetation from 8 of 12 major vegetational zones in Oregon and Washington, representing about 80% of the area of the two states, were studied along a latitudinal transect from the Pacific Coast
to the east slopes of the Cascade Mountains. Six stands were in forest zones, one...
Black cottonwood (Populus trichocarpa Torr. and Gray) cuttings were collected from five Oregon provenances along a partial north-south distribution of the species. Cuttings from each provenance were grown at two locations, one on the Willamette Valley floor, and the other on the Valley margin, for one year. Survival at both...
Sapling Douglas-fir trees on five sites in the Coastal and
Cascade Mountain ranges of Oregon were measured five times during
the year from the summer of 1977 through the spring of 1978 for
diurnal patterns of xylem water potential, stomatal conductance and
abscisic acid. Vapor pressure deficit and solar radiation...
Phellinus weirii, the cause of laminated root rot, is considered the most destructive root rot of Douglas-fir, but little is known about the damage it causes, to a forest. The objective of this study was to determine silvicultural impacts of P. weirii on a managed forest. A survey located and...
Three experiments were conducted on containerized seedlings to examine the short-term and long-term effects of environment on the root regeneration potential, and to examine the fate of the current photosynthate and its relationship to the root regeneration potential. The short-term effects were studied first in a 3x3x2 factorial experiment comprising...
Trees stressed by artificial and natural means were sampled for response in growth and vigor, carbohydrate content, resin pressure characteristics, and water relations. Tree response was found to reflect both the severity and type of stress imposed. Crown color and appearance were reliable indicators of prolonged stress and advanced decline...
A range-wide sample of 221 provenances of western hemlock (Tsuga heterophylla (Raf.) Sarg.) showed much variation in several characteristics. Variation in seed weight was significant, but not correlated with seed source latitude, elevation, or distance from the ocean. Variation in the frequency of 4-cotyledon seedlings was significant at
regional, provenance,...
This thesis is divided into three chapters. For all chapters, the experiments described deal with the responses of all or a subset
of 72 wind-pollinated Douglas-fir families from 36 different locations in southwestern Oregon. Wind-pollinated seed was collected from each of two trees at each of the 36 locations. The...
First season container-grown noble fir (Abies procera) and Shasta red fir (Abies magnifica var. shastensis) seedlings were given six combinations of shade (0%, 30%, and 50% shade) and irrigation (moist and dry) treatments in the nursery beginning in late July, 1977. To evaluate frost hardiness
development, destructive freezing tests were...
Seasonal variations in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) leaf weight and nitrogen content were measured in Oregon's Coast and western Cascade Ranges. Current and older foliage from thinned and unthinned stands were sampled monthly from October, 1978 to September, 1979. Changes in leaf weight per unit area of foliage and...
An understanding of the gibberellins present in Douglas-fir is essential to understanding and controlling the growth and development
of this species. A technique was developed which permits the separation of certain gibberellins with high performance liquid chromatography and their identification with mass spectrometry. An extraction technique
for the isolation of...
The relationship between Leaf Area Index (LAI) and current stem-wood
production was examined in selected stands in eastern
Washington. Stands were sampled with an angle gauge (prism). LAI
was estimated from sapwood area; current stem-wood production from
DBH, height, and radial increment.
Maximum LAI attainable on a given site has...
Lodgepole pine seedlings were used to test a general hypothesis of how water and nitrogen stress affect a plants' monoterpene composition. Four treatments, consisting of high and low levels of both water and
nitrogen, were applied to the trees. Growth measurements, consisting of shoot and needle lengths, needle fresh weights...
A systematic investigation was made of the distribution of short wave radiation within the crown of an open-grown Douglas-fir tree. The study tree was 23 years old, 14 meters tall and had a maximum crown diameter of about ten meters. Global radiation was measured every 15 cm along eight different...
The release of Douglas-fir from competition with snowbrush (Ceanothus velutinus Dougl.) has often been suggested as a way to improve conifer yield in the western Cascades. This study investigated this possibility by describing changes in the availability of water and light and the response of Douglas-fir to the changing environment,...
Several understory conununities display successional stages during the first two hundred years following logging or fire disturbance in the coastal Picea-Tsua forests of southeast Alaska. Residual shrubs
and tree seedlings increase their growth exponentially after overstory removal. Understory biomass peaks at about 5000 kghayr fifteen to twenty-five years after logging....
The control that stand leaf area exerts upon individual tree vigor was tested on a heterogeneous, even-aged Douglas-fir stand infected by Phellinus root rot. Tree vigor, or growth efficiency ratio, was defined as the current basal area growth per unit of leaf area. Because of a close relationship between sapwood...
A greenhouse bioassay was used to investigate effects of natural and manmade disturbances on native ectomycorrhizal populations of Douglas-fir and western hemlock on a steep southeast slope in the
west central Cascade Mountains. Total and mycorrhizal root tips were counted on seedlings grown in soils collected from (a) two 100+...
This research dealt with the direct environmental influence of atmospheric vapor pressure on stomates of Pseudotsuga menziesii, Picea engelniannii, and Fragaria X ananassa, and the indirect physiological
control of stomates by abscisic acid in Pseudotsuga menziesii. Two ventilated porometers (diffusion and steady-state) were compared on four broadleaf and five coniferous...
Red alder (Alnus rubra Bong.), scotch broom (Cytisus scoparius L.) and snowbrush (Ceanothus velutinus Dougi ) were planted under precommercially thinned Douglas-fir (Pseudotsuga iuenziesil Mirb Franco) in the central Oregon Cascades. Plug grown red alder had significantly greater survival than all wildling propagules except for
the second broom planting Browsing...
The relationship of sapwood basal area to basal area was examined on stands of young-growth Douglas-fir. Through non-destructive sampling, sapwood basal area was quantified on four different thinning intensities and one control (unthinned) treatment. Emphasis was on testing a sampling method and evaluating variations in the sapwood component as a...
The effects of dwarf mistletoe on fuel in precommercial ponderosa pine stands: Dwarf mistletoe and healthy stands were sampled by vertical planar intercept and whole tree biomass sampling techniques to measure
fuel loading in ground and crown fuels. Differences in size, distribution, and vitality of fuel were shown to depend...
Chapter 1 Growth and Survival of Root-Wrenched Douglas-fir Seedlings Root wrenching of seedlings (severing the roots 15 cm below the soil surface) was investigated as a nursery practice to improve growth and survival of field-planted Douglas-fir from six local seed sources
in the Pacific Northwest. At lifting, shoots of wrenched...
Preliminary fertilization trials with western hemlock have yielded responses which vary significantly from stand to stand, especially in areas near the Pacific Coast. Growth responses have varied from positive to negative in an erratic manner. Previous data did not permit validation of such hypotheses as, "the application of fertilizer
to...
Dimension analysis, acetylene reduction and canopy structure measurements were used to evaluate the relationship between density and dry weight production, nitrogen (N₂) fixation and photosynthate partitioning (as indicated by dimension analysis) in 5-year-old red alder (Alnus rubra Bong.) plantations established at three initial spacings. Density strongly affected most dry weight...
Cell aggregate size in both Douglas-fir and poplar suspension cultures was reduced by the addition of the chelator compounds EDTA and CDTA at concentrations under 100 ppm. Reduced cell aggregate size increased growth efficiency of suspension cultures of both species. Cell aggregates 550 j.z. or smaller in size were used...