Author: Richard William Robbins Publisher: ISBN: Category : Conifers Languages : en Pages : 192
Book Description
This study evaluated the effect of soil compaction on the growth of natural regeneration on volcanic ash-influenced soils in the southern Washington Cascades. Growth of 9 to 18 year-old sapling-. sized Ponderosa pine (Pinus ponderosa Laws.) was studied on sites ranging from 915 to 1006 m elevation in an area selectively logged in 1959, and for 10 to 13 year-old lodgepole pine (Pinus contorta Dougl.) established following a group selection harvest on a 1342 in elevation site logged in 1967. Soils ranged from loam to sandy loam texture. Height, diameter, and volume growth were measured for trees growing under an array of disturbance conditions to determine the influence of soil compaction on their size and growth rates. A number of soil, vegetation, and site variables were studied to determine possible cause and effect relationships with growth parameters. Bulk density of the surface 30.5 cm was measured within the lateral rooting zone to provide an index of compaction. Trees were destructively sampled to obtain a detailed record of their development, and to adjust for differences in age as a result of variable establishment delays. Average bulk density increases of 15.4 and 27.5 percent relative to adjacent undisturbed soil were found for skid trails in the ponderosa pine and lodgepole pine study areas, respectively. The effect of soil displacement overshadowed any possible relationship between bulk density and growth for lodgepole pine. The strong correlation of growth with organic matter content indicates that removal of nutrient-rich surface soil during logging and slash disposal operations may significantly affect site productivity, particularly for poorly developed skeletal soils. Regression analysis showed that several growth parameters for ponderosa p1ne were strongly associated with the increase in bulk density despite additional significant relationships with tree age, site index, and overstory cover. Reductions in total growth of 4.8, 7.7 and 20.4 percent were predicted for height, diameter, and stem volume of 14 year-old skid trail regeneration based on the mean bulk density increase. Evaluation of current growth increment was effective in adjusting for differences in tree age. Predicted average reductions in height, diameter, and volume growth of 7.1, 11.8, and 18.9 percent were estimated for young ponderosa pine based on the last five year period. Projected impacts from regression analysis represent conservative estimates, since the mean density increase used is the prediction model included measurements for sample trees growing in soil with bulk densities comparable to undisturbed levels. When the ponderosa pine sample was stratified into low and high impact groups based on bulk density increases, differences in the shape of height-age and diameter-age curves were apparent. A significant decrease in the rate of growth was noted for trees growing under highly disturbed conditions. Projected effects of compaction on site productivity throughout the rotation are difficult to assess, but measurable reductions in young tree growth coupled with frequent stand entries and the slow rate of natural soil recovery provide a basis for concern for long-term impacts.
Author: Wade H. Shafer Publisher: Springer Science & Business Media ISBN: 1468451979 Category : Science Languages : en Pages : 407
Book Description
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 1 957, 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 thought 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 29 (thesis year 1984) a total of 12,637 theses titles from 23 Canadian and 202 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 29 reports theses submitted in 1984, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Author: Margaret Gale Publisher: Gulf Professional Publishing ISBN: 9780444516343 Category : Nature Languages : en Pages : 354
Book Description
This collection represents a unique set of essays on the role of theory in shaping the practice of medicine across disciplinary boundaries. In the context of this volume, "theory” relates to the conceptual models, frameworks, knowledge representations, metaphors and analogies that inform the problem-solving efforts of practitioners seeking to develop novel dialogues both within and across disciplinary boundaries. Contributors to this volume include computational scientists, chemists, medical researchers, biologists and philosophers, all drawing on personal experience in their respective fields to produce a genuinely interdisciplinary range of perspectives on the common theme of theory in medical thinking and multidisciplinary research practice. * Selected and edited papers from the 10th North American Forest Soils Conference held in Saulte Ste. Marie, Ontario, Canada, July 20-24, 2003 * A unique spin-off from Elsevier's highly regarded journal, Forest Ecology and Management * An estimated 400 pages of the latest findings in forest soil ecology from the most prominent researchers in the field
Author: Richard William Robbins
Author: Wade H. Shafer
Author: Society of American Foresters. Convention
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Author: Society of American Foresters. Convention
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Author: Henry A. Froehlich
Author: Margaret Gale
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