Tropical island ecosystems have proven to be inordinately vulnerable to invasions by exotic plants and animals. Today these islands only contain small
remnant populations of the original flora and fauna, and these populations are facing increasing pressure from invasive plants. This paper attempts to answer four important questions whose solutions...
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...
In western Oregon, hardwood trees occupy 20% of the
timberland but account for less than 1% of the timber
harvest. Information about how to manage them effectively
is limited.
The objective of this study was to examine: 1)
effect of thinning on tree growth, plant moisture stress,
and crown cover...
Understory conifer regeneration needs to occur beneath conifer-dominated
canopies if two-storied or uneven-aged structures are to be considered for western
Oregon Coast Range stand management. To ensure adequate numbers of seedlings
to meet stocking or habitat structure objectives, planting may be a solution. We
undertook a multi-level study to determine...
The broadest goal of the research covered in this thesis was to contribute
to our limited knowledge of high elevation forest soil ecology. Based on the reeds
of funding agencies, specific objectives were to examine 1) how climate-induced
Abies lasiocarpa ([Hook.] Nutt.) forest expansion affects soil nutrient pools, 2) the...
This study was conducted to investigate why root disease centers east of the
Cascade crest tend to be larger in diameter and more abundant than their counterparts to
the west, within subalpine forest stands of central Oregon. The trend in a 290 km² study
area appeared opposite of what was...
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional
watersheds is needed to provide a foundation for forest management strategies
aimed at conserving native biodiversity. I examined influences of environmental variability
and disturbance history on forest structure and composition in the Cummins Creek
Wilderness, located on the central Oregon...
Fire history and fire regimes were reconstructed for a 450 km² area in the central
western Oregon Cascades, using tree-ring analysis of fire scars and tree origin years at
137 sampled clearcuts. I described temporal patterns of fire frequency, severity, and size,
and interpreted topographic influences on fire frequency and...
