http://hdl.handle.net/1957/21686 2013-05-20T02:41:56Z 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/. 2013-01-05T00:00:00Z 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/. 2013-01-01T00:00:00Z http://hdl.handle.net/1957/37162 Hydroclimatic and hydrochemical controls on Plecoptera diversity and distribution in northern freshwater ecosystems Kruitbos, Laura M.; Tetzlaff, Doerthe; Soulsby, Chris; Buttle, Jim; Carey, Sean K.; Laudon, Hjalmar; McDonnell, Jeffrey J.; McGuire, Kevin; Seibert, Jan; Cunjak, Richard; Shanley, Jamie Freshwater ecosystems in the mid- to upper-latitudes of the northern hemisphere are particularly vulnerable to the impact of climate change as slight changes in air temperature can alter the form, timing, and magnitude of precipitation and consequent influence of snowmelt on streamflow dynamics. Here, we examine the effects of hydro-climate, flow regime, and hydrochemistry on Plecoptera (stonefly) alpha (a) diversity and distribution in northern freshwater ecosystems. Wecharacterized the hydroclimatic regime of seven catchments spanning a climatic gradient across the northern temperate region and compared them with estimates of Plecoptera genera richness. By a spacefor- time substitution, we assessed how warmer temperatures and altered flow regimes may influence Plecoptera alpha diversity and composition at the genus level. Our results show wide hydroclimatic variability among sites, including differences in temporal streamflow dynamics and temperature response. Principal component analysis showed that Plecoptera genera richness was positively correlated with catchment relief (m), mean and median annual air temperature ( C), and streamflow. These results provide a preliminary insight into how hydroclimatic change, particularly in terms of increased air temperature and altered streamflow regimes, may create future conditions more favorable to some Plecopteras in northern catchments. 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 Springer and can be found at: http://www.springer.com/?SGWID=0-102-0-0-0. 2012-04-15T00:00:00Z http://hdl.handle.net/1957/36162 Current and Potential Tagging and Tracking Systems for Logs Harvested from Pacific Northwest Forests Murphy, Glen; Clark, Joshua A.; Pilkerton, Stephen The forest industry is constantly changing, and technology is constantly shifting the bar for efficiency and profitability. To maintain competitiveness and control costs in a global market, an efficient log tracking method must be used by regional stakeholders in the log supply chain from stump to mill to end consumer. It is important to understand the implications of recent innovations in log tracking for stakeholders in the Pacific Northwest in the context of a global economy, and how innovations in other regions may affect the future of log tracking. In this report, we (1) discuss the importance of log tracking technology, (2) review both regional and international efforts to harness technology for tracking logs from stump to mill, (3) report on a regional survey that examines the current status of log tracking in the Pacific Northwest, and (4) identify the most promising technologies that could be implemented in the near future. The majority of regional stakeholders use paper tags or other relatively simple tagging methods. Radio frequency identification (RFID) tags and other tracer technologies were not used when marking, sorting, tracking, or paying for logs by any of the regional organizations responding to the survey. RFID tags and spray-on code marking show promise for the near future. 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 Society of American Foresters and can be found at: http://www.safnet.org/. 2012-04-01T00:00:00Z