The link between aboveground net primary productivity (ANPP) and resource gradients generated by complex terrain (solar radiation, nutrients, and moisture) has been established in the literature. Belowground ecosystem stocks and functions, such as soil organic carbon (SOC), dissolved organic carbon (DOC), and belowground productivity have also been related to the same topography and resource distributions, and therefore it is expected that they share spatial and temporal patterns with ANPP. However, stand structure on complex terrain is a function of multiple trajectories of forest development that interact with existing resource gradients, creating feedbacks that complicate the relationships between resource availability and ANPP. On a 96 ha forested watershed in the H.J. Andrews Experimental Forest in the Western Cascades range of Oregon, spatiotemporal heterogeneity in the secondary succession of a replanted Pseudotsuga menziesii stand following harvest results from the interaction of stand composition and abiotic drivers and may create unique "hot spots" and "hot moments" that complicate gradient relationships. In this dissertation, I tested the hypotheses that (chapter 3) multiple successional trajectories exist and can be predicted from a general linear model using specific topographic, historical, and biological parameters and that an estimated "maximum ANPP" may better represent stand characteristics than ANPP measured at a particular moment in time. I also test that (chapter 4) the distribution of light fraction carbon (LFC; C with a density of less than 1.85 g/cm��) is spatially variable, elevated on hardwood-initiated sites (hardwood biomass > 50% of biomass), and positively correlated with litter fall and ANPP. Chapter 4 also tests that heavy fraction carbon (HFC; C with a density of greater than 1.85 g/cm��) is a function of both soil mineralogy, stand composition, and ANPP, such that edges observed spatially in site mineralogy (changes in soil type) are reflected in sharp changes in the composition of the forest community and the magnitude of HFC stores. Finally, I hypothesized (chapter 5) that in complex terrain, dissolved organic carbon (DOC) export can be predicted from landform characteristics, relates to ANPP, and may be measured by several methods which are well-correlated with one another. In chapter 6, I discuss how litter fall measurements can be extrapolated to a watershed extent, and use litter fall as an example of the error that can occur in scaling up measurements taken at a small scale, within a heterogeneous stand on complex terrain, to a landscape scale extent. / Graduation date: 2013

Snow melt is an important component of Western US water resources, accounting for about 50-80% of the annual runoff. Prediction of runoff from snowmelt in heterogeneous watersheds requires the quantification of physical processes accounting for the effects of forest canopy on snow accumulation, melt and sublimation. The forest canopy intercepts snowfall that resulting in smaller snow accumulations in forest area than in open area. The forest canopy also modifies the energy exchange between snow surface and the atmosphere, and alters the sublimation and melting of sub-canopy snow relative to open area. This dissertation has examined ways to improve snowmelt modeling capability to better account for canopy effects and has presented enhancements to an energy balance model that include i) an improved representation of the transmission of radiation through the canopy, ii) an improved representation of the atmospheric transport of heat and water vapor between the snow on the ground, in the canopy and the atmosphere above, and iii) an improved representation of the processes of canopy snow interception and unloading. These enhancements were evaluated against 4 years of field data (2006-2010) collected at the TW Daniels Experimental Forest (TWDEF) located 30 miles N-E of Logan. Observations included continuous automated climate and snow depth measurements supported by periodic field measurements of snow water equivalent and temperature in four different vegetation classes (grass, shrubs, coniferous forest, deciduous forest). The enhanced canopy components were included into the Utah Energy Balance Snowmelt model and provide improved capability to predict the surface water input and runoff from snowmelt in heterogeneous watersheds using a parsimonious approach that can be used with practically available information.

Thesis (M.A.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains viii, 82 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 45-48).

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 99-110). Also available on the World Wide Web.

Thesis (M.S.)--Marshall University, 2002. / Title from document title page. Document formatted into pages; contains x, 52 p. with maps and illustrations. Includes bibliographical references (p. 48-52).

Thesis (M.S.)--Oregon State College, 1954. / Typescript. Includes bibliographical references (leaves 50-51). Also available on the World Wide Web.

ix, 94 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / This thesis examines the Long-Term Ecological Reflections at H.J. Andrews Experimental Forest, Oregon, a project that promotes creative inquiry at an ecological research station. I analyze how reflective writing contributes to a deeper understanding of ecosystem processes and fosters a closer connection to nature, referred to as "ecological awareness." I argue that the greatest ecological awareness comes from a combination of scientific and artistic ways of knowing as well as physical immersion in nature. I critically analyze the work of four writers: Jane Coffey, Vicki Graham, Freeman House, and Robin Kimmerer. These works create a strong connection to place for the reader and facilitate an understanding of the forest ecosystem through a discussion of scientific facts. They also create a sense of place through vivid and metaphorical language. These reflections will become an increasingly valuable mode of inquiry as the Andrews Forest develops a stronger writer-scientists interaction. / Committee in Charge: Dr. Louise V. Westling, Chair; Dr. Brendan Bohannan; Dr. Scott D. Bridgham

The effect of altitude on individual storm precipitation in some of the San Dimas experimental watersheds is investigated. It is found that there is a well- defined increase of storm precipitation with altitude for storms greater than one inch. This increase is a linear function of storm depth. Using 41 storms of different magnitudes, a precipitation -altitude relationship is derived for a small area in the San Dimas Experimental Forest. The regionalization of this relationship and its transferability are tested by analyzing differences (errors) between computed and observed storm precipitation values in each case. In testing the regionalization of the precipitation- altitude relationship by computing mean areal storm precipitation over a larger area the standard error of estimate is around 11 percent. In transfering the same relationship the results are not as good and give a standard error of 16 percent. For individual points, however, the error is much higher. A rainfall- runoff model is used as a tool for evaluating the effect of precipitation errors, on simulated streamflow, in a watershed of 4.5 square miles. For annual flows, errors range between 3.4 and 12.3 percent while errors in simulated monthly flows are as high as 22 percent. It is also evident that there is a strong dependence of the error magnitude on the state (wet, dry, etc.) of the preceding year or months, whichever is applicable. An error propagation is observed as a result of consistently over -estimating the precipitation input to the model. This evaluation is more of a qualitative nature and the values of error given should be viewed in this sense.

Mat-forming ectomycorrhizal (EcM) fungi represent a prevalent constituent of many temperate forest ecosystems and create dramatic changes in soil structure and chemistry. EcM mat soil have been shown to have increased microbial respiration rates and have been hypothesized to harbor unique assemblages of fungi and bacteria. The objectives of this dissertation were to characterize and examine the fungal and bacterial communities associated with EcM mats in old-growth forests of the H.J. Andrews Experimental Forest located in the Oregon Cascades. Additionally, this work assessed the application of traditional, emerging, and novel molecular sampling techniques for determining microbial communities of environmental samples. This research investigated the microbial communities associated with two common EcM mat genera found in old-growth Douglas fir stands in the Pacific Northwest; Piloderma (Atheliales, Basidiomycota) and Ramaria (Gomphales, Basidiomycota). Soil samples were collected from Piloderma and Ramaria mats and surrounding non- mat soil for molecular analysis of nucleic acids. First, a comparative study was conducted to determine the most appropriate rDNA molecular sampling technique for microbial community characterization. Two next-generation sequencing methods, Roche 454 pyrosequencing and Illumina-based environmental sequencing, the latter developed by the author, were compared to a more traditional sequencing approach, i.e., Sanger sequencing of clone libraries. These findings informed the subsequent sampling of the fungal ITS and bacterial 16S rDNA fragment with 454 pyrosequencing to determine the microbial communities within mat and non-mat soils. Second, this work utilized a pyrosequencing approach to explore fungal community structure in EcM mat and non-mat soils. This work concluded that differences in microbial communities do exist between Piloderma mat, Ramaria mat, and non-mat soils, but the differences are largely quantitative with relatively few distinct taxonomic shifts in microbial constituents. Piloderma, Ramaria and Russula, in addition to being the dominant taxa found on mycorrhizal root tips, were found to be the most abundant taxa in bulk soils within their respective mat types or non-mat sample. The background fungal communities within the EcM mats in this study exhibited considerable taxonomic overlap with the exception of Piloderma vs. non-mat comparisons; Russula species dominated nonmat soils but tended to be excluded or significantly underrepresented in Piloderma mats. Lastly, this study explored the bacterial communities associated with Piloderma and Ramaria mats using lower- coverage 454-Jr pyrosequencing. Bacterial communities exhibited significant structure as a function of mat-type, soil horizon and pH, but this finding should be interpreted with respect to the nonrandom distribution of Piloderma-mats in the O- horizon and the Ramaria-mats in the A-horizon, and the tendancy for EcM mats to be more acidic than surrounding soils. Nonetheless, the total microbial (bacterial and fungal) community was typically dominated by the mat-forming taxa, or Russula, in the case of non-mat soils. While the presence of Piloderma mats did enrich or restrict some bacterial groups, soil pH was also found to be a significant driver of bacterial richness and taxonomic diversity. Fungal and bacterial richness were also found to be positively related to one another, regardless of soil horizon or EcM mat type. This work, taken together, contributes to the understanding of hyperdiversity and heterogeneity of microbial communities of temperate forest soils and highlights the potential for fungal and bacterial communities to be influenced by the presence of EcM mats. / Graduation date: 2012

In an initial research proposal of December 1969, the scientists of the Coniferous Forest Biome (CFB), an ecosystem study centered in the Pacific Northwest and part of the larger International Biological Programme (IBP), expressed optimism that computer simulations and systems modeling could transform empirical knowledge of the carbon, water, and nutrient flows turned into viable forest management practice. The CFB's strategy aimed to use projections of the computer simulations and data from field study to constantly check and direct each other, resulting in a flexible, refined, and accurate understanding of forest ecosystems, as well as a reliable guide to forest management. To what extent did the CFB's research program, centered on a total system model, complete its cycle of field study, modeling, and validation? Despite the innovative strategies of the CFB modelers, ecosystem modeling lost its preeminent status among the goals of the CFB, due to different interpretations of the purpose and philosophy of ecosystem modeling and the practical limitations of administering a large research program. Instead, small field-based studies during the CFB yielded a number of ground-breaking discoveries. Although they diverged from the modeling objectives, these areas of fieldwork emerged from questions the forest's functions and cycling processes that the modeling efforts of the CFB required. Focusing on the work of CFB participants from Oregon State University and the USDA Forest Service in the H. J. Andrews Experimental Forest, this thesis addresses the relationship between the marginalization of the modeling objectives and the rising centrality of field-based forest studies in the CFB from 1969 to 1980. Given the ongoing legacy of CFB research at the Andrews Long-Term Ecological Research (LTER) site and the later implications of CFB findings in debates over forest policy and management, this thesis also seeks to evaluate the Coniferous Forest Biome as a whole and discuss the role of modeling and field work within large ecological research endeavors more generally. / Graduation date: 2006