Published March 1974. A more recent revision exists. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Two objectives of this research were to identify fungi which are
mycorrhizal with western hemlock and to examine the ecology of hemlock
mycorrhizal fungi indigenous to outplanting sites. Another objective
was to evaluate the effectiveness of mycorrhizal inoculation in
improving the performance of outplanted hemlock seedlings.
A list of over...
Using clones to regenerate a species new to clonal reforestation presents the forest manager with many problems. A number of interrelated and interdependent research and development activites are needed to answer these technical questions. Network diagraming was used for scheduling research activities and for indicating interdependencies among activities. The resultant...
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...
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,...
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,...
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...
Hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) is an arboreal, hemiparasitic plant that principally parasitizes western hemlock (Tsuga heterophylla). Hemlock dwarf mistletoe exerts a profound influence on infected trees that can drastically change the structure of the tree crown due to reduced growth, top dieback, branch deformation and death, resulting...
The advantages of high-temperature drying are faster drying, reduced inventory, reduced energy requirements, and reduced equilibrium moisture content. However the disadvantages are higher initial costs of the kiln, greater power needs, knot dropout, and reduction in some strength properties. The latter was the subject of this study. Three hundred pieces...
A decreasing rate of flow was observed (after sufficient air and particulate matter were removed from the wood and water) under steady-state conditions for green western hemlock sapwood. The decrease is theorized to be due to viscoelastic behavior of pit membranes. An unsteady-state procedure for determining longitudinal liquid permeability of...
Young western hemlock stands in the Coast Range of Oregon will
contribute to the commercial timber supply of the region in the
future, the extent of the contribution depending on environmental
and cultural factors. The relative diameter and volume growth of
crop-trees in the stands will be increased substantially by...
Variability in wood properties causes boards within a stack of lumber to
dry at different rates and reach different moisture content levels after drying is
completed. The consequence is that the boards will have properties that differ from
ones that were intended to be achieved by the drying process.
The...
The response of western hemlock (Tsuga heterophylla [Raf.] Sarg.) to two methods of site preparation for planting was compared. One site was cleared of mature brush by the "brown-crush-and-burn" method. The other was partially cleared by spraying with herbicides. Seedlings lifted and planted in December, January, February, and April were...
Logs are seedbeds for trees in many Picea sitchensis-Tsuga
heterophylla forests of Washington and Oregon. Factors affecting this
close association, including seed retention and seedling establishment
on logs and successional changes in log characteristics, are explored
In this study.
Field and laboratory experiments indicated that competition with
vegetation on the...
A thermomechanical pulp, a high yield sulfite pulp, and a high yield solvent sulfite pulp from western hemlock [Tsuga heterophylla (Raf.) Sarg.] wood were investigated to determine the amount of carbohydrate material present and to elucidate the structures of the carbohydrates. The effects of the three pulping processes, which were...
This study concerns the effect of pre-harvest killing of commercial
sized, forty year old western hemlock (Tsuga heterophylla
(Raf.) Sarg.) on subsequent stump infection by Fomes annosus (Fr.)
Karst. Further evaluations were made on tree drying, loosening of
bark, wood deterioration and rate of crown and cambial death. Findings
on...
Patterns of western hemlock regeneration were studied in relation to forest structural development and environment in the Oregon Coast Range. Density of western
hemlock seedlings was examined across the climatic gradient from cool, moist coastal
areas to the seasonally hot and dry Willamette Valley Margin. Seedling densities were most strongly...
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...
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...
The growth of western hemlock during the first four
years of seedling establishment was examined in a competitive
environment in which seedlings were exposed to various types
of animal damage and salmonberry and/or alder competition.
The study utilized an existing Nelder/replacement series
experiment which focused on the competitive effects among...
Wood modulus of elasticity (MOE), also known as wood stiffness, is one of the most important wood properties. Wood stiffness is a measure of the resistance to deflection, and is important because some products such as laminated veneer lumber, plywood, and dimension lumber require stiff and strong wood. Incorporating wood...
Indentation hardness tests were made on sections of 211 pieces
of Douglas fir and 208 pieces of Western hemlock at a moisture content
of about 11 percent. Specific gravity and visual-density evaluations
were also determined.
Correlation coefficients for linear regression of density, as
measured by specific gravity, on average standard...
The rate and manner of bioniass loss from decomposing Douglas-fir and western hemlock boles in mid-elevation forests of the central Cascade Range were measured. Bole bark and wood were considered separately. Loss of bole wood due to respiration was measured by change in bole wood density. Loss of bole wood...
Reforestation of Pacific Northwest forest-lands with western hemlock has been hindered by unexplained plantation failures.
The purpose of this thesis is to provide information that will help in determining the cause of seedling damage and mortality. The studies focused on the relationship between xylem water potential, xylem cavitation and the...
Western hemlock-Sitka spruce forests, where prior precommercial thinning has occurred, constitute one of the most productive
young-growth management types along the Pacific Coast from Oregon to southeast Alaska. These stands are ready for a first commercial thinning entry, however, the costs and benefits of such entries and resulting impacts at...
The steadily increasing costs of raw materials, of the treated products, and of their replacement in service, as well as the steadily shrinking supply of preferred species, prompted a forum at Oregon State University on May 15, 1973 "to encourage the use of western hemlock and western fuss for poles...
Western hemlock forests in the coastal areas of Oregon are some of the most productive and diverse forests in the world. This rich diversity represents both a challenge and an opportunity for woodland owners interested in managing western hemlock on their property.
Western hemlock and Sitka spruce are relatively thin-
barked species and susceptible to damage during thinning
operations. Damage to the wood allows decay-causing fungi
to enter resulting in loss of merchantable volume at the
time of final harvest. Cable yarding systems are needed for
much of the thinning because most...
A survey was made in Oregon and Washington of the discoloration occurring in noble fir and Western hemlock wood, and the present data are presented as an aid in the inspection of these woods for aircraft and other high-grade lumber.
Recommendations, based on strength tests of similar discolorations in spruce...
These are the proceedings of a short course in the management of young Douglas-fir and western hemlock conducted by the School of Forestry, Oregon State University, June 16-18, 1969.
Upon recommendations of participants in the 1968 short course, this course was designed to enlarge upon the inventory, operational, and economic...
These are the proceedings of the fifth short course in managing young forests in the Douglas-fir region, conducted by the School of Forestry, Oregon State University, June 11-13, 1973.
Knowledge and experience in the management of young forests continues to expand. The short courses are designed to keep pace with...
These are the proceedings of a short course in the management of young Douglas-fir and western hemlock conducted by the School of Forestry, Oregon State University, June 16-18, 1969.
Upon recommendations of participants in the 1968 short course, this course was designed to enlarge upon the inventory, operational, and economic...
Douglas-fir and western hemlock growth and stocking were examined on two neighboring clear-cut watersheds in the Western Cascades of Oregon and related to the intensity of burning and logging disturbance, habitat type, soil type, aspect and the influence of percent cover of both invading Ceanothus species and residual Acer circinatum....
Most of the methods currently used to measure root respiration introduce various disturbances which may lead to biased results, and require destruction of roots which does not permit repeated measurements of root growth and respiration. A root box method was developed for measurement of root respiration, as well as root...
Moisture content and shrinkage were determined on specimens equilibrated at two conditions for equilibrium moisture content (EMC) at room temperature after the specimens had been dried under a variety of constant temperatures with constant EMC's. Moisture content at room temperature equilibrium was less for specimens dried at high temperature than...
To test the effects of kiln-drying on strength properties of Douglas fir and western hemlock, temperatures to 230 F, conditions for equilibrium moisture contents of 6 percent and 12 percent, and prolonged heating were investigated.
Prolonged heating and choice of conditions for 6 percent or 12 percent equilibrium moisture content...
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade tolerant species, were compared to learn more about the temporal pattern of release from suppression in both species, whether hydraulic architecture or photosynthetic capacity constrain release and how wood functional properties change...
The hemlock woolly adelgid, Adelges tsugae, is causing widespread mortality of eastern hemlock, Tsuga canadensis, in the eastern United States. In the West, A. tsugae causes negligible damage to western hemlock, Tsuga heterophylla. Host tolerance traits and presence of endemic predators may be contributing to the relative tolerance of western...
The purpose of this study was to assess how growth of young to mature Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sar.)
in mixed stands was influenced by the presence of residual trees. Fourteen paired plots with
and without residual trees were examined in a retrospective...
The fixed bed drying of western hemlock and Douglas-fir biomass particles at temperatures ranging from 50°C to 200°C and air velocities from 0.3 to 0.9 m/s was investigated. The objectives were to describe the drying characteristics of the particles, fit a model for thin-layer drying, and develop and test a...
Hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahi) G.N. Jones subsp. tsugense (western hemlock race)) is the most important and widespread disease of old-growth western hemlock forests in the Pacific Northwest. Although heavy infection of dwarf mistletoe can significantly increase growth loss and mortality of host trees, the parasite is also considered...
This study evaluated the effects of partial cutting on stand structure and growth,
patterns of conifer regeneration, stand mortality and disease, and understory plant diversity
and abundance. Seventy-three 1/5 ha plots were established in 18 partially cut stands
throughout southeast Alaska. These stands were partially cut 12 to 96 years...
A mathematical and then a numerical model were developed for simulating a convective batch lumber drying process. The model incorporates mass and heat transfer relationships within the lumber stack, as well as thermodynamic properties of the wood and drying air. It takes into account a change of air properties along...
Western redcedar, western hemlock, and Douglas-fir seedlings were transplanted into pots in one of two soils representative of high and low levels of available NO3 (and total N). The soils were collected from sites at Cascade Head (Oregon Coast) and Wind River (Washington Cascades). Whole plant and component relative dry...
Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually lead to tree death. To investigate the long-term impacts of dwarf mistletoe on gas exchange of host western hemlock trees, I compared growth, gas...
The objectives of this study were to determine the species composition and density of natural conifer regeneration following selective logging in southeast Alaska.
Therefore, we quantified the density and size of new cohort spruce and hemlock and current seedling bank in 17 selectively logged stands. All stands were in mixed...
I studied the water relations traits, twig conductivity, C'3 isotopic composition,
and wood density of three conifer and five angiosperm species in western Oregon. This
study took place from spring 2002 to fall 2003 on four sites. Species were selected to
represent the diversity of drought tolerance of woody plants...
Described as one of the most destructive pathogens of agricultural crops and forest trees, Phytophthora is a genus of microorganisms containing over 100 known species. Phytophthora alni has caused collar and root disease in alders throughout Europe and a form of the species has recently been isolated in North America....
Using existing permanent research plot data, we developed equations for predicting height-to-crown-base (HCB), 5-yr diametergrowth rate (delta D), 5-yr height-growth rate (delta H), 5-yr mortality rate (PM), and the maximum size-density trajectory for Douglasfir and western hemlock in the coastal region of the Pacific Northwest. With the exception of the...
The role of riparian forests in maintaining temperatures of headwater streams is well established and is a foundation of forest practice rules designed to protect streamwater quality. However, detailed investigation is still needed quantifying specific characteristics of stream systems that affect streamwater temperature including riparian features, stream morphology, and subsurface...
Stream temperature, as an important component of stream ecosystems, can be affected by forest harvesting through removal of riparian shade and changes in hydrology. Riparian Management Areas
(RMAs), as implemented through the current Oregon Forest Practice Rules, are designed, in part, to maintain stream temperature following forest harvesting. However, effectiveness...