Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 11, 2008) Includes bibliographical references.

Thesis (M.S.)--Ohio University, June, 2005. / Includes bibliographical references (p. 73-81)

Thesis (M.S.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 73-81)

Thesis (M.S.)--University of Wisconsin -- La Crosse, 2006. / Includes bibliographical references (leaves 69-73)

A two-year study was conducted to collect and identify hypovirulent isolates of the chestnut blight fungus (Cryphonectria parasitica) from American chestnut trees located in the Great Smoky Mountains National Park (GRSM). During the survey, 339 isolates were obtained, 54 of which had abnormal morphological characteristics in culture and 3 of these contained dsRNA. Analysis of vegetative compatibility divided all 339 isolates into 34 distinct groups, 16 of which only contained a single isolate. A total of 19 isolates (compared to 3 controls) containing abnormal cultural morphologies or dsRNA were randomly selected for use in a field trial containing 44 natural occurring healthy American chestnut trees in the Nantahala National Forest, North Carolina. Following artificial inoculation during spring of 2007, data on canker radial growth and stromata production were obtained monthly for six months. Results from the field trial indicated that 5 of the isolates, 3 of which contained dsRNA, were potentially hypovirulent based on appearance and canker growth rates compared to the controls. Data from the field trial and VC pairings indicated that one isolate, 236-1C, has potential for use as a biological control agent for the chestnut blight fungus in the GRSM, but is limited to select VC groups. Since numerous VC groups occur in the park, additional hypovirulent isolates must be identified which form anastomosis with the majority of the important groups before large scale control can succeed.

Surface mining for coal in the Appalachian region has removed over 0.6 million Ha of mixed mesophytic forest. Successful reforestation would be beneficial, but questions remain concerning application of reclamation and reforestation methods on operational scales. Four experiments were performed testing these methods on newly reclaimed and previously reclaimed, but unused, former mines. On newly reclaimed sites, loose grading during reclamation reduced erosion and increased plant community diversity compared to smooth grading. Seeding only annual ryegrass (Lolium multiflorum) for erosion control, along with tree planting, increased plant community diversity and improved survival and growth of hybrid American chestnut (Castanea dentata x Castanea mollissima), compared to conventional seeding. Surface water infiltration was positively correlated with herbaceous ground cover. On older mines, subsoil ripping to alleviate compaction improved tree survival and growth, in some cases, after five growing seasons. Of the three species groups planted, including Eastern white pine (Pinus strobus), mixed native hardwoods had the best survival and hybrid poplar (Populus deltoides x Populus trichocarpa) produced the most biomass. Hybrid American chestnuts survived and grew better when planted as bare-root seedlings than when planted as ungerminated nuts in tree tubes, demonstrating the potential for planting bare-root chestnut seedlings along with other species when reforesting reclaimed surface mines. This can aid in restoring American chestnut, functionally extinct since the blight (Cryphonectria parasitica), to its former range. These cultural practices can be employed to accelerate reforestation of mined lands, but many questions remain about their capability to fully restore ecosystem structure and processes. / Master of Science

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xv, 168 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 142-149).

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