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...
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...
Selective suppression of crown and root sprouting of
non-coniferous cover are the keys to effective forest
vegetation management. This study 1) develops insight into
mechanisms of controlling root suckering and top regrowth of
bear clover (Chamaebatia foliolosa), and develops a broad
data base for controlling broad groups of vegetation
chemically....
Evaluation of meta-sedimentary bedrock as a source of stored water available
to plants in a mediterranean climate is presented based on: root length distribution
(RLD), root morphology, rock water holding capacity and seasonal pattern of water
depletion. Studies were performed in southwestern Oregon under young stands of
whiteleaf manzanita, ponderosa...
The main objective of this study was to evaluate the interaction between
herbaceous competition, fertility, and seed source on Douglas-fir survival and
growth. A secondary objective was to evaluate the effect of these various factors
on the production of lammas shoots and the selectivity of deer browse. Finally,
the role...
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...
To improve the efficiency of herbicide
applications, each stage of the spray application
process must be considered. Two of these stages, the
process of spray deposition within plant canopies and
the influence of the form of the spray deposit on
efficacy were investigated.
The effect of droplet size, spray volume,...
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...
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...
This thesis examines the competitive aspects of Douglas-fir trees growing with two commonly associated competitors--red alder and grass--at varying densities. Two Nelder plots in three different environments in the Oregon Coast Range were studied. The sites represented the warm, dry climate of the Willamette Valley; the warm, moist climate of...