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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.
1

The imprint of coarse woody debris on soil biological and chemical properties in the western Oregon Cascades

Spears, Julie D. H. 03 April 2002 (has links)
The abundance and spatial heterogeneity of coarse woody debris (CWD) on the forest floor is a prominent feature of Pacific Northwest (PNW) forest ecosystems. The effect of CWD on soil solution chemistry, nutrient cycling and availability, soil physical structure and formation of soil organic matter, however, remains unknown. Therefore, studies on the spatial and temporal imprint of CWD on forest soils are timely and can fill critical gaps in our understanding of the role of CWD in PNW forest ecosystems. I investigated the effect of CWD on soils and soil solution at the H.J. Andrews Experimental Forest in a two-part study. Mineral soils were sampled beneath CWD to a depth of 60 cm. The top 15 cm of soil was also repeatedly sampled for seasonal differences. Control leachate, CWD leachate and soil solution from control soils and from under CWD were collected from the fall of 1999 until the spring of 2001. Results indicated that CWD leachates were much more acidic than water leaching from the forest floor without CWD. Intermediate stages of CWD decomposition had the highest concentrations of hydrophobic compounds and polyphenols of all stages of decay. Correspondingly, surface soils sampled from under well-decayed CWD were more acidic and had more exchangeable acidity and aluminum, and a lower percent base saturation than soils under the forest floor. Nutrient pools were not different under CWD, although nitrogen fluxes were slower under CWD. Although we had hypothesized that the spatial variability of CWD inputs may affect forest soils under CWD, we found that the spatial variability is much more temporal than I had hypothesized and is limited to the top five centimeters of the underlying soil. / Graduation date: 2002

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