Vegetation-environmental Relationships on Two Clearcuts on the Western Slopes of the Oregon Cascades

Vegetation-environmental Relationships on Two Clearcuts on the Western Slopes of the Oregon Cascades
Author: Dawn M. Egeland
Publisher:
Total Pages: 222
Release: 1985
Genre: Douglas fir
ISBN:

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. The nitrogen content of the surface soil, both total and mineralizable nitrogen, and current and year old Douglas-fir foliar nitrogen contents as percent dry weight were determined. Total nitrogen content was determined by micro-kjeldahl techniques. Mineralizable nitrogen was obtained through anaerobic incubation at 40 C for seven days. Douglas-fir establishment and growth were not limited on severely burned or compacted sites. A strong preference for unburned sites was shown by western hemlock, however. Appreciable Douglas-fir stocking, basal diameters, basal areas and relative densities were supported by Rhma/Gash, Acci/Gash and Cola habitat types. Cola communities also contained the greatest western hemlock stocking and basal area values. Soil type influenced Douglas-fir but not western hemlock. Largest Douglas-fir basal diameters, basal areas and relative densities were found on lateritic soil types. Both Douglas-fir and western hemlock stocking were favored on northerly exposures, though the basal diameters of Douglas-fir were maximized on level and westerly aspects. The percent cover of snowbrush (Ceanothus velutinus), redstem ceanothus (C. sanguineus), deerbrush (C. integerrimus) and vine maple (Acer circinatum) was also examined in relation to site factors. Cover values of all Ceanothus species were highest on disturbed and! or burned sites. For the most part, the three Ceanothus species had varying preferences in terms of habitat type, soil type and aspect expressed as degrees of cover. Percent vine maple cover was only influenced by burning and habitat type, preferring sites undisturbed by burning and Rhma/Gash, Acci/Gash and Acci/Bene communities in which it was also an important component before logging. Nultiple regressions indicated that no site factor, shrub cover or nitrogen variable accounted for more than sixteen percent of the total explained variation in conifer growth or stocking. Site factors could explain the most variation. greater Douglas-fir basal diameters occurred on plots with snowbrush cover, while the presenee of redstem ceanothus was associated with lower Douglas-fir basal diameters, basal areas and relative densities. The presence of Ceanothus species was generally not associated with increased soil or foliar nitrogen content, though Douglas-fir year old needles showed slightly higher mean values on sites with redstem ceanothus. Plots containing vine maple, however, contained greater quantities of mineralizable nitrogen. Nitrogen data indicates that though total soil nitrogen levels appear adequate for Douglas-fir nutrition, mineralizable and foliar nitrogen may be limiting at least during the growing season. While partially ameliorated, results suggest that the effects from harvesting and slash burning have yet to subside, though factors including habitat type, soil type and aspect are becoming increasingly- important in determining the distribution of shrub cover as well as the growth and establishment of Douglas-fir and western hemlock.

Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences
Author: Wade H. Shafer
Publisher: Springer Science & Business Media
Total Pages: 386
Release: 2012-12-06
Genre: Science
ISBN: 1461573912

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thougtit that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 31 (thesis year 1986) a total of 11 ,480 theses titles trom 24 Canadian and 182 United States universities. We are sure that this broader base tor these titles reported will greatly enhance the value ot this important annual reterence work. While Volume 31 reports theses submitted in 1986, on occasion, certain univer sities do re port theses submitted in previousyears but not reported at the time.

Forest Ecosystems

Forest Ecosystems
Author: David A. Perry
Publisher: JHU Press
Total Pages: 631
Release: 2008-07-24
Genre: Nature
ISBN: 0801888409

2009 Outstanding Academic Title, Choice This acclaimed textbook is the most comprehensive available in the field of forest ecology. Designed for advanced students of forest science, ecology, and environmental studies, it is also an essential reference for forest ecologists, foresters, and land managers. The authors provide an inclusive survey of boreal, temperate, and tropical forests with an emphasis on ecological concepts across scales that range from global to landscape to microscopic. Situating forests in the context of larger landscapes, they reveal the complex patterns and processes observed in tree-dominated habitats. The updated and expanded second edition covers • Conservation • Ecosystem services • Climate change • Vegetation classification • Disturbance • Species interactions • Self-thinning • Genetics • Soil influences • Productivity • Biogeochemical cycling • Mineralization • Effects of herbivory • Ecosystem stability