The growth and productivity of British Columbia’s interior forests is largely limited by soil nutrient availability. Fertilization has been shown to be an effective silvicultural tool for increasing the development of immature stands throughout the region. This has lead to increased interest in long-term, repeated fertilization as a means of addressing timber-supply shortfalls as a result of the current mountain pine beetle (Dendroctonus ponderosae) outbreak. However, there is little information related to the impacts of repeated fertilization on the cycling of nutrients in many of these stands. This study makes use of a long-term (13-15 year) fertilization experiment in two lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm) and two interior spruce (Picea glauca [Moench] Voss and Picea engelmannii Parry) forests in the central interior of British Columbia subject to two levels (periodic and annual) of nitrogen(N)-based fertilization. The primary goal of the project was to examine the effects of different fertilizer regimes on aspects of soil chemistry. Specifically, this project was concerned with the impacts of repeated fertilization on: 1) soil carbon (C) and N cycling, and 2) soil base cation (e.g., Ca, Mg & K) availability. Soil and foliar nutrient regimes were quantified throughout the 2008 and 2009 growing seasons using ion-exchange membrane (IEM) plant root simulator (PRS) probes and traditional soil and foliar analyses. Fertilization increased N cycling at all sites, with generally elevated soil and foliar N and significant soil-foliar N relationships in several cases. Nitrate (NO3 -) increased in the fertilized plots in several cases; however, there was minimal evidence of NO3 - leaching. Greater than 90% of fertilizer-N inputs were retained onsite, suggesting these forests are not N-saturated. Soil, tree and total ecosystem C generally increased in response to fertilization, with the spruce sites exhibiting greater C accrual per unit of fertilizer N than the pine sites. Further, significant linear relationships between soil C and N were evident at all sites. At sites with poorly buffered soils (pH < 4), fertilizer treatments generally led to increased soil acidification and decreases in soil and foliar Ca. Decreases in soil Ca may have been due to significant increases in sulfate leaching; whereas foliar Ca decreases appear to be related to compromised uptake systems, potentially from increased soil aluminum. Buffering capacities, rather than forest type, appear to be the best predictor of soil and foliar Ca responses to fertilization. Despite significant changes in soil chemistry at all four sites, it does not appear that current fertilization rates are detrimentally affecting tree growth. / Graduate

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 136-151). Also available on the World Wide Web.

Thesis (M.Sc.) --University of Adelaide, 1933. / Typewritten copy.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "May, 2008." Includes bibliographical references (leaves 39-44). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1993. / Includes mounted photographs. Typescript (photography). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 69-74). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 130-143). Also available via the Internet.

Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 71-77). Also available on the World Wide Web.

Thesis (Ph. D.)--Michigan State University. Dept. of Forestry, 2008. / Title from PDF t.p. (viewed on July 7, 2009) Includes bibliographical references (p. 171-191). Also issued in print.

Thesis (Ph. D.)--Ohio State University, 2007.