Forest growth models in the Pacific Northwest are predominantly empirical. Predictions of yield under alternative silvicultural regimes cannot rely completely on field trials; yet empirical growth models are often inadequate for extrapolating untested regimes and genotypes. The limitations of current models include (1) long time-steps (e.g. 5-10 years); (2) insufficient...
Current studies suggest that perfluorinated organic compounds, such as fluorotelomer alcohols (FtOHs) in the troposphere, may be precursors of perfluorocarboxylic acids and perfluorosulfonates in remote regions. Fluorinated organic compounds were investigated in archived extracts collected from remote locations in Okinawa, Japan (HSO) and Mount Bachelor, Oregon (MBO) during the springs...
The general emphasis of this work has been synthesis, characterization, and applications of n- and p-type inorganic oxide thin films that are deposited from solutions. In particular, a study of n-type transparent semiconductor films of tin (IV) oxide and zinc-doped tin (IV) oxide has been performed by spin coating. Solution...
The Gd3+ ion has been used to induce quantum splitting in luminescent
materials by using cross-relaxation energy transfer (CRET). In Nd:LiGdF4, quantum
splitting results from a two-step CRET between Gd3+ and Nd3+, first involving a
transition 6G→6I on Gd3+ and an excitation within the 4f3 configuration of Nd3+
followed by...
Solid state luminescent sulfides are prepared as powders in order to elucidate the relationship between structure and light emission. While the sulfides studied in this dissertation are known phosphors, materials are investigated in a variety of new ways. Elementary properties and structures of MgS are reviewed, and preparation of MgS...
The variegated aqueous chemistries of metal cations are applied to the design and synthesis of non-toxic solution precursors suitable for additive printing of large-area oxide electronics. Polycondensation behaviors of aqueous Al+3 and PO4 +3 are manipulated in the deposition of atomically smooth amorphous aluminum oxide phosphate (AlPO) dielectric films. AlPO...
Northeastern Oregon geology and climate provides moderately productive conditions for forest management and timber production. Although site preparation and planting are commonly used silvicultural practices, little research exists on the efficacy of specific forest herbicides and responses of seedling survival and growth in this region. This research seeks to improve...
Knowledge of stand structure, stand dynamics, and production ecology of species mixtures lags well behind that of single-species, even-aged stands. Two mixed-species spacing trials in central Oregon allowed investigation of mixed-species dynamics in a controlled experimental setting. The first site, Pringle Butte, is a mixture of ponderosa pine (Pinus ponderosa...
The objective of this project was to investigate the fate of ponderosa pine regeneration from seed to established seedling, and to determine the relative influences of several important stand elements on those fates. The project was carried out in a series of observational and experimental recruitment studies in central Oregon....
The behavior of coniferous trees subjected to wind loading was investigated through a series of experiments and also through simulation modeling. Previous studies that measured the natural oscillation frequencies and damping ratios were reviewed and equations were developed for predicting the natural frequency of a tree from the ratio of...