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Private forest landowners own the largest share of the forest land in the United States. Future timber supply requires forest management and investment by these private forest landowners. Since private forest landowners are diverse, understanding the factors affecting the forest management decisions of these individuals is important. Two analyses are presented in this study to characterize the forest management decisions of West Virginia NIPF landowners and to understand their forest management decisions. The data for the study was collected from a mail survey conducted in August 2005 to 2100 landowners in West Virginia. The survey resulted in 244 useful responses, a 20% response rate. v

The 'global warming' effect has been found to influence vegetation phenological processes. Heat island phenomenon associated with urbanized area presents a unique place to investigate its local warming effects. This study compares the date of budburst (DOBB) of street London plane trees (Platanus 6 acerifolia) between highly urbanized New York City (NYC) and relatively less urbanized Ithaca, New York in 2007 and 2008. It also linked DOBB with land surface temperature and fractional vegetation cover derived from Landsat satellite images. The DOBB in NYC and Ithaca differed significantly as budburst occurred 3 and 4 days earlier in NYC than in Ithaca in 2007 and 2008, respectively. The intensity of the heat island effect and its effect on tree phenology were greater in NYC. Results show that DOBB can be explained by temperature, and findings could be extrapolated to make inferences on the potential impact of global warming on vegetation communities.

The 4d transition metal oxide, NbO2, is a key material for a wide range of potential applications. It exhibits a thermally driven metal-to-insulator transition (MIT) with very high transition temperature (TMIT = 1083 K). High TMIT, electric field induced sharp threshold switching and current-controlled negative differential resistance (NDR) characteristics makes this material most suitable for current switching devices. Metal-to-insulator transition in NbO2 is accompanied by a structural transition from a rutile (high temperature) to a tetragonal (low temperature) structure with lowering temperature. In this work, pulsed laser deposition growth of NbO2 thin films and their structural and electrical characterization were investigated. To study the switching mechanism in epitaxial NbO2 (110) film lateral devices, 20 nm thick films were grown by pulsed laser deposition on Al2O3 (0001) substrates. The Ar/O2 total pressure during growth was varied to demonstrate the gradual transformation between NbO2 and Nb2O5 phases, which was verified using x-ray diffraction, x-ray photoelectron spectroscopy, and optical absorption measurements. Electrical resistance threshold switching in current characteristics was studied in a lateral geometry using interdigitated Pt top electrodes to preserve the epitaxial crystalline quality of the films. Volatile and reversible transitions between high and iii low resistance states were observed in epitaxial NbO2 films, while irreversible transitions were found in the case of Nb2O5 phase. Electric field pulsed current measurements confirmed thermallyinduced threshold switching. Switching mechanism in the polycrystalline thin film of NbO2 was also investigated. Polycrystalline thin films were grown on the TiN coated SiO2/Si substrate using pulsed laser deposition. Thickness and contact size dependent study in threshold switching in current characteristics of NbO2 films grown using different growth pressures were performed. Threshold switching and current oscillations produced by the films having different defect densities were measured and compared. To increase defect density, such as oxygen vacancies, films grown in different growth pressures or using different oxygen mass flow ratios were used. Finally, electrical properties of the polycrystalline thin film were compared with the epitaxial films grown using similar growth conditions. The epitaxial film was grown on Si-doped GaN coated substrate where Si:GaN layer acted as the bottom contact. Pulsed I-V as well as the input voltage dependent and time dependent frequency measurements were performed and compared with each other. Stability and switching rapidity of the thin film vertical devices were analyzed and compared in terms of the defect density presented in the film. iv DEDICATION v ACKNOWLEDGMENTS First, I would like to express my gratitude to my advisor Prof. David Lederman for his uninterrupted guidance during this project. Without his continuous support and supervision, this dissertation would not have taken this form. I am grateful ...