Over the last decade a new perspective on how forest ecosystems operate has emerged. Ecosystems appear much more flexible than we once thought. Even the most persistent is still evolving in composition. Yet for all their diversity, very similar processes are seen as operating in all forests, providing a point...
Although there has been extensive research on the geomorphic and ecologic role of
large woody debris (LWD) in streams, the dynamics of LWD in streams are poorly
known due to various measurement difficulties during floods. In this thesis I present the
results of two flume experiments on the dynamics of...
Respiratory rates were measured, in situ, for the litter, the
soil, and the litter-soil subsystems of a Pseudotsuga menziesii forest
as a function of type of understory vegetation. The major objectives
were to demonstrate the utility of the litter layer as a distinct subsystem
of this forest ecosystem, to demonstrate...
Numerous isolates of Armillaria mellea were obtained within
a 250 by 450 foot Study Area in a ponderosa pine plantation in central
Oregon. These isolates were recovered from roots of armillaria-killed
young-growth pine, from large stumps of the former pine
overstory, including roots away from the stump proper, and from...
The initial distribution of organic arsenical silvicides was
measured in the trees, litter and soil of four forest types in the
Pacific Northwest following a standard, precommercial chemical
thinnning. Factors which influenced the persistence, movement or
fate of these compounds were noted and used to evaluate differences
in the generalized...
Riparian communities in the southern portion of Malheur National
Forest were intensively studied with the objective of designing an approach for
classifying disturbed riparian areas into units of similar potential. Not all
riparian community types in this portion of the Blue Mountains were sampled
due to time limitations. Some of...
Despite the critical ecological roles of structural features in forests, ecologically
relevant quantitative measures of structure that allow comparisons among forest stands
are still limited. A new index, the structural complexity index (SCI), was developed to
characterize and compare the structural complexity of different forests. Point patterns
of stem-mapped trees...
Riparian zones are ecotones between terrestrial and aquatic ecosystems. Processes in streams are strongly influenced by riparian forest communities, age, stage and structure. Temperate forests across much of North America, including riparian areas, are recovering from historic land clearing with many stands in the stem-exclusion phase of development in which...
This study has been concerned with the patterns of vegetative changes which occur during the first five years following logging and burning on Douglas-fir clear cuts. Knowledge of the successional sequence in the coastal forests of western Oregon is of primary importance to those concerned with the management of this...
A study was undertaken in the Marys Peak watershed with the
following objectives. First, a classification of the major plant communities
was carried out. Second, some of the ecological features
of Acer circinatum that account for its distribution within these
communities were determined. The following plant communities
are described:
Corylus...
Seven sites of uniform topography and soil were selected within
a self perpetuating ponderosa pine forest found on the eastern
flank of the central Oregon Cascades. These plots were located along
a vegetational gradient caused mainly by an orographic rain shadow.
Data gathered included density, frequency, and cover for all...
The overall goal of this study was to investigate influences of ectomycorrhizae (EM) and
interspecific carbon transfer on seedling performance in species mixtures. The objectives were to:
(I) determine the potential for EM to link paper birch and Douglas-fir, (ii) quantify gross and net
interspecific carbon transfer, and (iii) evaluate...
Nitrogen, phosphorus and sulfur concentrations were measured in the soil, foliage and litter of Douglas-fir growing in pure Douglas-fir and mixed conifer stands. On four sites of contrasting fertility and climatic conditions, plots had been modified by the introduction of alder, thinning, or by a single application of nitrogen fertilizer...
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 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+...