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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Vegetation community development eight years after harvesting in small streams buffers at the Malcolm Knapp Research Forest

Miquelajauregui, Yosune 05 1900 (has links)
Riparian areas connect terrestrial and aquatic environments. The objectives of this research were to compare the vegetation community composition and structure eight years after harvesting and to explore successional trends among buffer widths at year eight after disturbance and in a chronosequence. A series of small clearcuts were harvested in 1998 in a 70 year old second growth stand at the Malcolm Knapp Research Forest and 0m, 10m and 30m reserve zones were established adjacent to the streams. Each treatment was replicated 3 times and 3 unharvested streams were identified as controls. Overstory and understory vegetation was measured annually from the year of harvest. Canopy density was measured using a densiometer. For comparative purposes, four vegetation plots were added in riparian areas within an 1868 and an old-growth stand during the summer of 2006. Eight years after harvesting, understory vegetation development is affected by buffer width due to higher light levels, and species richness in the 10m and 0m buffers is higher than in the 30m buffer and control. Shrubs and deciduous trees dominate the 0m and 10m buffer treatments. Proximity to the stream does not affect the composition and abundance of species with the exception of herbs and mosses. In the 10m and 30m buffer treatments, up to 15% overstory trees were windthrown in the first 2 years after harvest producing large canopy gaps. Consequently, the understory development in the 10m and 30m buffers is more like that in the 1868 and old-growth stands than in the controls, but these treatments still lack the very large trees and microsite heterogeneity of the older stands. In the unharvested controls, self-thinning continues and there has been 30% mortality of mostly smaller trees over the past 8 years. However, overstory density remains high. The 0m buffer was quickly colonized by shrubs and ferns and within the last 2 years has become dominated by juvenile deciduous trees. Overall, the 10m buffer balances timber production with the maintenance of overstory and understory structure dynamics. The combined effect of light from the edge and partial windthrow is accelerating succession towards a more mature or ‘old-growth’ condition.
72

Remote sensing of vegetation dynamics in response to flooding and fire in the Okavango Delta, Botswana

Neuenschwander, Amy Lynn, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
73

Auswirkungen des Douglasienanbaus auf die Bodenvegetation im nordwestdeutschen Tiefland /

Budde, Sabine. January 2006 (has links)
Zugl.: Göttingen, University, Diss., 2006.
74

A geobotanical study of the remnant natural vegetation of temperate South Australia /

Sparrow, Ashley. January 1991 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Botany, 1992. / Includes bibliographical references (leaves 187-205).
75

The environmental impacts of seismic exploration in the Cooper Basin, upon lignum, Muehlenbeckia florulenta and spinifex, Triodia basedowii : a pilot study /

Horton, Malcolm, January 1998 (has links) (PDF)
Thesis (M. Env. Sc.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999. / Includes bibliographical references (leaves 183-191).
76

Canadian vegetation response to climate and projected climatic change /

Lenihan, James M. January 1992 (has links)
Thesis (Ph. D.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 163-176). Also available online.
77

Airborne videography as a classification and validation technique for Landsat TM-based vegetation mapping /

Barrett, Charley, January 1998 (has links)
Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 73-79). Also available on the World Wide Web.
78

Long-term functional trait dynamics in abandoned agricultural fields /

Rye, Timothy A., January 2008 (has links) (PDF)
Thesis (M.S.)--Eastern Illinois University, 2008. / Includes bibliographical references (leaves 48-59).
79

Effects of weed control on vegetation dynamics in Pacific Northwest conifer plantations /

Chen, Fen-Hui. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes bibliographical references. Also available on the World Wide Web.
80

Three methods for estimating subpixel cover fractions in coarse resolution imagery /

Damon, Diane L. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references (leaves 30-33). Also available on the World Wide Web.

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