http://hdl.handle.net/1957/10900 Research findings from faculty, staff, and students in Forest Engineering, Resources and Management. Thu, 16 May 2013 10:31:26 GMT 2013-05-16T10:31:26Z http://hdl.handle.net/1957/38559 Stand development, fire and growth of old-growth and young forests in southwestern Oregon, USA Sensenig, Thomas; Bailey, John D.; Tappeiner, John C. We studied stand development in three distinct forest types in southwestern Oregon using six stands each in uncut and clear-felled old-growth stands and nearby young stands (18 total). Old-growth stands showed a wide range of tree ages (>300 years) and low tree densities for several centuries; rapid early growth produced trees with large crowns and diameters, as well as low height-to-diameter ratios. In contrast, young stands established much quicker and at higher tree densities; beyond their initial 20 years, trees had smaller diameters at equivalent ages, slower growth rates, smaller crowns and higher H:D than trees in old-growth stands. Low-intensity disturbance, likely dominated by fire, was common in oldgrowth stands during their early development. Fire scars showed these stands burned frequently from 1700 to 1900, and low levels of tree recruitment occurred in a complex relationship with fire during this 200 years. There was no evidence of fire, however, in either old-growth or young stands after 1909, and their densities were well above that of 1900; in old-growth stands, 15–25% of the basal growth occurred from 1950 to 1990, and it appears that they are on a development pathway different from what they experienced from 1700 to 1900. Furthermore, tree recruitment has been limited in both old-growth and young stands since 1950 while biomass and fuels continue to accumulate rapidly. Past stand dynamics can be emulated by prescribed fire and light thinning to reduce risk of loss from severe fire or insects, as well as to partially restore stand conditions that existed prior to fire exclusion. Our results suggest that young stands can be grown to produce high levels of biomass/wood, or their development can be altered to more closely follow that of old-growth stands depending on management objectives. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Sat, 05 Jan 2013 00:00:00 GMT http://hdl.handle.net/1957/38559 2013-01-05T00:00:00Z http://hdl.handle.net/1957/37902 Keying forest stream protection to aquatic ecosystem values in multi-ownership watersheds Pickard, Brian R. Forested lands of western Oregon provide aquatic habitat for many fish and riparian dependent species, including a wide variety of salmon species. Current policies set riparian protections using fixed buffers on streams for federal and private lands based on stream type or size. These buffers can create a series of disjointed riparian protections, as federal lands require buffers that are much larger than private lands. In addition, the fixed buffer approach is neither flexible nor tailored to aquatic ecosystem values. This thesis presents a framework for comprehensively assessing stream networks using site specific watershed features and then suggests riparian conservation strategies that key stream and riparian protection to aquatic ecosystem values. Seven study watersheds were used in this analysis, totaling over 2.5 million acres of forested lands in western Oregon. Employing a set of geospatial tools, called NetMap, streams in each watershed were classified into higher and lower priorities using criteria of intrinsic potential, erosion/debris flow susceptibility, and thermal loading potential. Results demonstrated the inherent variability within and among watersheds based on the geomorphic and ecological processes determined important for selected salmon species. Within each watershed, both federal and non-federal lands had many miles of higher priority fish-bearing and non-fish bearing streams, suggesting the need for comprehensive, holistic watershed conservation strategies. Based on the partitioning of streams into higher and lower priorities, an alternative riparian conservation strategy was then modeled for federal lands that allocate protection on the basis of the ecological context of a stream segment’s potential and particular location while still meeting federal aquatic conservation goals and objectives. Possible increases to the land base for long-term timber production were then identified if this strategy were applied to federal Matrix lands. Results demonstrated that 8-30 percent of the current riparian buffers could be reallocated to the land base for long-term timber production. An additional 26-45 percent of current buffers could be managed simultaneously for both timber production and aquatic ecosystem goals. Results also provided a framework for targeting of conservation and restoration efforts towards higher priority streams within each watershed. As many of the most ecologically important streams were located on non-federal lands, riparian conservation policies focused on streams classified as higher priority on those lands may be needed to protect aquatic species and their environments. Graduation date: 2013 Fri, 15 Mar 2013 00:00:00 GMT http://hdl.handle.net/1957/37902 2013-03-15T00:00:00Z http://hdl.handle.net/1957/37602 Modeling Relative Humidity in Headwater Forests Using Correlation with Air Temperature Eskelson, Bianca N. I.; Anderson, Paul D.; Temesgen, Hailemariam Microclimate variables such as air temperature and relative humidity influence habitat conditions and ecological processes in riparian forests. The increased relative humidity levels within riparian areas are essential for many plant and wildlife species. Information about relative humidity patterns within riparian areas and adjacent uplands are necessary for the prescription of effective buffer widths. Relative humidity monitoring is more expensive than temperature monitoring due to greater sensor costs, and it is primarily conducted for research purposes. To make relative humidity monitoring in riparian areas more cost effective, we explored modeling relative humidity as a function of air temperature and other covariates using linear fixed and linear mixed effects models applied to two case studies. Localizing predictions for stream reaches using a linear mixed effects model or a linear fixed effects model with correction factor improved model predictions, especially when large variability among stream reaches was present. A minimum of three to five relative humidity measurements per stream reach seem sufficient to estimate the random stream reach effect or correction factor for the linear mixed and linear fixed effects models, respectively. Including covariates that describe distance to stream and canopy cover in addition to air temperature improved model performance. Although further model refinement is probably needed to allow detection of small changes in relative humidity associated with changes in stand structure from partial overstory removal, the models developed provide a means towards decreasing the costs of monitoring microclimates of importance to riparian area function. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Northwest Scientific Association and can be found at: http://www.northwestscience.org/. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1957/37602 2013-01-01T00:00:00Z http://hdl.handle.net/1957/37209 Evaluation of six tools for estimating woody biomass moisture content Becerra Ochoa, Fernando Amador Woody biomass transportation costs and market values/costs are strongly correlated with the woody biomass moisture content. Properly managing moisture content can potentially lead to economic and environmental advantages in biomass energy markets. Good management requires accurate moisture content measurements. Therefore, availability of accurate, precise, reliable, and efficient tools to assess woody biomass moisture content is essential. In this study, six different tools (Fibre-Gen HM200, IML Hammer, Humimeter BLW, Timbermaster, Humimeter HM1 and Wile Bio Meter) were evaluated. The six tools employed three different measurement technologies; acoustic, conductance, and capacitance. Woody biomass samples were collected over one season (summer 2011) at three different locations in western Oregon (Corvallis, Dallas, and Clatskanie) for three softwood species and three hardwood species: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Ponderosa pine (Pinus ponderosa L.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), hybrid poplar (Populus spp.), Madrone (Arbutus spp.), and Garryana Oak (Quercus garryana Dougl. ex Hook). Twenty 3-meter long log (20 to 400mm diameter) specimens were collected per species; 18 specimens were divided into two different treatments (open vs. covered), and the two remaining specimens were chipped. In addition, approximately 100 kilograms per species of hogfuel (limbs and tops) were collected and chipped. Moisture content measurements of logs, chips, and hogfuel were made regularly over a four month period. These data was used to develop multiple linear regression models for assessing the moisture content of the six species using the six tools. The major factors considered in the regression models were species (6), treatment (2), and tools (6). The data were also used to estimate the sample size needed for each tool. The best tool from each technology type was identified. The results generated from this study show that (1) none of the tools are accurate without calibration for different species, (2) the best model/tool combination could only explain about 80% of the variability in measurements, (3) further product development is required in some cases to ensure that the tools are robust for industrial application, and (4) there is a wide range in efficiency of the tools (i.e., 50 minute tool efficiency range). The Fibre-Gen HM200 and Wile Bio Meter were the most accurate, precise and efficient tools tested. The cost of transporting woody biomass from the forest to woody biomass plants is "optimized" when the moisture content drops to approximately 30% (wet basis). Validation of the models developed for three of the tools tested (Fibre-Gen HM200, Humimeter BLW and the Wile Bio Meter) indicates that the tools are accurate below 35% MC (wet basis). This suggests they could be used for making threshold transportation decisions, i.e., determining when to haul. Graduation date: 2013 Thu, 13 Dec 2012 00:00:00 GMT http://hdl.handle.net/1957/37209 2012-12-13T00:00:00Z