The effectiveness of sapwood basal area as an estimator of individual
tree basal area growth was tested on several young, even-aged
Douglas-fir stands, stocked at varying densities. For all densities,
ranging from partially open-grown to very overstocked stands, the
null hypothesis that there was no association between sapwood basal
area...
Stocking characteristics and heights attained by tree
seedlings at ages five and seven were measured on 45 study
units, representing five habitat types, established on
clearcuts in the Abies amabilis zone in the Western Cascades
of Oregon. The study units ranged from six to 30 acres in
size, seven to...
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...
An experimental reintroduction was performed to determine the best method to create new populations of the tuberous species Perideridia erythrorhiza, a rare vascular plant endemic to southern Oregon. Only a handful of sites are currently present, and many of these are subject to other land uses such as urban development...
I studied developmental rates in a suite of temperate and tropical passerine bird species from the New World to test the hypothesis that tropical passerines exhibit slower patterns of growth and development than temperate birds. I also investigated how the expression of several developmental rates varied with life history traits...
Lichens play many important roles in subarctic terrestrial ecosystems by fixing nitrogen, colonizing rock and gravel, stabilizing otherwise bare soil, adding significantly to vegetation biodiversity and serving as the primary food for caribou in the winter. In these chapters, I analyzed lichen community and ecological trait structure along environmental gradients,...