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Full-Text Articles in Physical Sciences and Mathematics
Data From: Forest Density Intensifies The Importance Of Snowpack To Growth In Water-Limited Pine Forests, Kelly E. Gleason, John B. Bradford, Anthony W. D’Amato, Shawn Fraver, Brian J. Palik, Michael A. Battaglia
Data From: Forest Density Intensifies The Importance Of Snowpack To Growth In Water-Limited Pine Forests, Kelly E. Gleason, John B. Bradford, Anthony W. D’Amato, Shawn Fraver, Brian J. Palik, Michael A. Battaglia
Environmental Science and Management Datasets
Research Study
Warming climate and resulting declines in seasonal snowpack have been associated with drought stress and tree mortality in seasonally snow-covered watersheds worldwide. Meanwhile, increasing forest density has further exacerbated drought stress due to intensified tree-tree competition. Using a uniquely detailed dataset of population-level forest growth (n=2495 sampled trees), we examined how inter-annual variability in growth relates to snow volume across a range of forest densities (e.g., competitive environments) in sites spanning a broad aridity gradient across the United States. Forest growth was positively related to snowpack in water-limited forests located at low latitude, and this relationship was intensified …
Modeling Post-Fire Successional Trajectories Under Climate Change In Interior Alaska Using Landis Ii, Shelby A. Weiss
Modeling Post-Fire Successional Trajectories Under Climate Change In Interior Alaska Using Landis Ii, Shelby A. Weiss
Systems Science Friday Noon Seminar Series
Alaska boreal forest ecosystems are experiencing a greater frequency of wildfire relative to the region’s historic fire regime. These increases in fire frequency, as well as annual burned area, increase the probability of forests re-burning within shorter intervals than were experienced historically. Such changes to the fire regime have the potential to shift successional trajectories in this ecosystem. To better understand potential changes in vegetation composition following short-interval, repeat fires, we are using LANDIS-II, a forest landscape model, to simulate changes in forest composition in response to climate change and increasing fire frequency. This seminar will include a description of …
Developing A Representative Snow-Monitoring Network In A Forested Mountain Watershed, Kelly E. Gleason, Anne Nolin, Travis R. Roth
Developing A Representative Snow-Monitoring Network In A Forested Mountain Watershed, Kelly E. Gleason, Anne Nolin, Travis R. Roth
Environmental Science and Management Faculty Publications and Presentations
A challenge in establishing new ground-based stations for monitoring snowpack accumulation and ablation is to locate the sites in areas that represent the key processes affecting snow accumulation and ablation. This is especially challenging in forested montane watersheds where the combined effects of terrain, climate, and land cover affect seasonal snowpack. We present a coupled modeling approach used to objectively identify representative snow-monitoring locations in a forested watershed in the western Oregon Cascades mountain range. We used a binary regression tree (BRT) non-parametric statistical model to classify peak snow water equivalent (SWE) based on physiographic landscape characteristics in an average …
Foliar Nutrient Concentrations Related To Soil Sources Across A Range Of Sites In The Northeastern United States, Melissa S. Lucash, Ruth D. Yanai, Joel D. Blum, B. B. Park
Foliar Nutrient Concentrations Related To Soil Sources Across A Range Of Sites In The Northeastern United States, Melissa S. Lucash, Ruth D. Yanai, Joel D. Blum, B. B. Park
Environmental Science and Management Faculty Publications and Presentations
Understanding the supply of nutrients from various soil sources and the sensitivity of tree species to soil nutrient availability is critical for predicting the effects of declines in base cations due to acid rain and forest harvesting on forest health and productivity. We collected soil samples from 19 sites in the northeastern United States, chemically analyzed them using a sequential extraction procedure, and compared them to the chemical composition of foliage of the dominant tree species. Concentrations of Ca and Mg in foliage were correlated with exchangeable Ca and Mg concentrations in the upper mineral soil; for most tree species …
Nutrient Uptake By Intact And Disturbed Roots Of Loblolly Pine Seedlings, Melissa S. Lucash, Ruth D. Yanai, J. Devereux Joslin
Nutrient Uptake By Intact And Disturbed Roots Of Loblolly Pine Seedlings, Melissa S. Lucash, Ruth D. Yanai, J. Devereux Joslin
Environmental Science and Management Faculty Publications and Presentations
Most measurements of nutrient uptake use either hydroponic systems or soil-grown roots that have been disturbed by excavation. The first objective of this study was to test how root excavation affects nitrate uptake. Rates of NO3− uptake by mycorrhizal loblolly pine (Pinus taeda L.) seedlings were measured in intact sand-filled columns, hydroponics, and disturbed sand-filled columns. Total nitrate uptake in intact sand-filled columns was higher than in disturbed columns, indicating that disturbance lowers uptake. Transferring plants from the sand-filled columns to hydroponics had little effect on NO3− uptake beyond delaying uptake for an hour. The second objective of this study …
Estimating Nutrient Uptake By Mature Tree Roots Under Field Conditions: Challenges And Opportunities, Melissa S. Lucash, Dave M. Eissenstat, J. Devereux Joslin, Karis J. Mcfarlane, Ruth D. Yanai
Estimating Nutrient Uptake By Mature Tree Roots Under Field Conditions: Challenges And Opportunities, Melissa S. Lucash, Dave M. Eissenstat, J. Devereux Joslin, Karis J. Mcfarlane, Ruth D. Yanai
Environmental Science and Management Faculty Publications and Presentations
Nutrient uptake by roots of mature trees is difficult to measure accurately under field conditions using existing methods. In this review, we discuss current techniques for measuring uptake at the root surface including excised roots, isotopic tracers, autoradiography, depletion, and lysimeters. Although these methods have provided many insights, each has drawbacks. Estimates of uptake are affected by the sampling scheme, experimental conditions, whether roots are excised or not, concentrations of ions, and the rate of efflux of ions. Microbes and mycorrhizas can also affect estimates of uptake. A greater focus on methods development is critical to advancing our understanding of …
Temporal Variation In Nutrient Uptake Capacity By Intact Roots Of Mature Loblolly Pine, Melissa S. Lucash, J. Devereux Joslin, Ruth D. Yanai
Temporal Variation In Nutrient Uptake Capacity By Intact Roots Of Mature Loblolly Pine, Melissa S. Lucash, J. Devereux Joslin, Ruth D. Yanai
Environmental Science and Management Faculty Publications and Presentations
Nutrient uptake is generally thought to exhibit a simple seasonal pattern, but few studies have measured temporal variation of nutrient uptake capacity in mature trees. We measured net uptake capacity of K, NH+ 4, NO 3 −, Mg and Ca across a range of solution concentrations by roots of mature loblolly pine at Calhoun Experimental Forest in October 2001, July 2001, and April 2002. Uptake capacity was generally lowest in July; rates in October were similar to those in April. Across a range of concentrations, antecedent nutrient solution concentrations affected the temporal patterns in uptake in July but not in …