A5041469800- Plant Water Relations and Carbon Dynamics
- Fire effects on ecosystems
- Tree-ring climate responses
- Forest ecology and management
- Rangeland and Wildlife Management
- Cryospheric studies and observations
- Hydrology and Watershed Management Studies
- Ecology and Vegetation Dynamics Studies
- Soil and Water Nutrient Dynamics
- Soil Carbon and Nitrogen Dynamics
- Isotope Analysis in Ecology
- Plant Pathogens and Fungal Diseases
- Seedling growth and survival studies
- Fish Ecology and Management Studies
- Forest Management and Policy
- Climate change and permafrost
- Botany and Plant Ecology Studies
- Plant Physiology and Cultivation Studies
- Forest Insect Ecology and Management
- Conservation, Biodiversity, and Resource Management
- Atmospheric and Environmental Gas Dynamics
- Plant tissue culture and regeneration
- Hydrology and Sediment Transport Processes
- Soil and Unsaturated Flow
- Land Use and Ecosystem Services
Oregon State University
1991-2023
University of Idaho
2009-2021
Clarkson University
2018
Texas A&M University
2015-2018
SUNY College of Environmental Science and Forestry
1993
State University of New York
1993
Midday stomatal closure is mediated by the availability of water in soil, leaf and atmosphere, but response to these environmental internal variables highly species specific. We tested hypothesis that differences humidity soil can be explained two parameters: leaf-specific hydraulic conductance (K(L)) a threshold potential (Psi(threshold)). used combination original published data estimate characteristic values K(L) Psi(threshold) for four common tree have distinctly different behaviors:...
The objectives of this study were to assess the range genotypic variation in vulnerability shoot and root xylem Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings water-stress-induced cavitation, trade-off between cavitation conductivity per unit stem cross-sectional area (k(s)), both within a species an individual tree. occupies broad environments exhibits considerable genetic for growth, morphology, drought hardiness. We chose two populations from each varieties (the coastal var....
Soil water potential (Psi(s)) is often estimated by measuring leaf before dawn (Psi(pd)), based on the assumption that plant status has come into equilibrium with of soil. However, it been documented for a number species stomata do not close completely at night, allowing nocturnal transpiration and thus preventing soil-plant equilibration. The nighttime necessitates testing equilibration accepting Psi(pd) as valid estimate Psi(s). We determined magnitude disequilibrium between Psi(s) in four...
Morse, W. C., J. L. Schedlbauer, S. E. Sesnie, B. Finegan, C. A. Harvey, Hollenhorst, K. Kavanagh, D. Stoian, and Wulfhorst. 2009. Consequences of environmental service payments for forest retention recruitment in a Costa Rican biological corridor. Ecology Society 14(1): 23. https://doi.org/10.5751/ES-02688-140123
Current operational methods for predicting tree mortality from fire injury are regression-based models that only indirectly consider underlying causes and, thus, have limited generality. A better understanding of the physiological consequences heating and needed to develop biophysical process can make predictions under changing or novel conditions. As an illustration benefits may arise including processes in fire-caused mortality, we a testable, hypothesis explaining pervasive patterns...
Abstract Diel fluctuations can comprise a significant portion of summer discharge in small to medium catchments. The source these signals and the manner which they are propagated stream gauging sites is poorly understood. In this work, we analysed from 15 subcatchments Dry Creek, Idaho, Reynolds HJ Andrews, Oregon. We identified diel low flow, determined lag between evapotranspiration demand seasonal trends evolution at each site. vegetation water use streamflow response increases throughout...
The following study investigates the timing and mechanism of impact Swiss needle cast on Douglas‐fir ( Pseudotsuga menziesii ) physiology (i.e. gas exchange). is a foliar disease caused by fungus Phaeocryptopus gaeumannii , which occurs throughout range Douglas fir until recently has been considered unimportant. However, recent surveys show currently affects > 52611 ha forested lands in western Oregon, USA, causing reduction growth c . 23% or an implied loss c. 3.2 m 3 −1 yr for 1996...
High foliar nitrogen concentration ([N]) is associated with high rates of photosynthesis and thus tree productivity; however, at excessive [N], productivity reduced. Reports [N] in the Douglas-fir forests Oregon Coast Range prompted this investigation growth needle physiological responses to increasing N concentrations 1-year-old seedlings. After 1 year fertilization, total seedling biomass increased each successive increase fertilizer concentration, except highest fertilization treatment....
Improved understanding of the physiological mechanisms tree mortality following fires is important with predicted increase in wildfires under climate change, as well continued use prescribed fire for forest management. Disruption water transport xylem from exposure to heat plume a has been hypothesized mechanism delayed mortality. This rapidly increases vapor pressure deficit canopy, increasing transpiration and tension on causing cavitation, thus reducing leading eventual death. We aimed...
Spatial variation in microclimate caused by air temperature inversions plays an important role determining the timing and rate of many physical biophysical processes. Such phenomena are particular interest mountainous regions where complex physiographic terrain can greatly complicate these Recent work has demonstrated that, some plants, stomata do not close completely at night, resulting nocturnal transpiration. The following was undertaken to develop a better understanding cold drainage its...
We investigated differences between wildfires and prescribed fires in their effects on nitrogen (N) dynamics mineral soils collected from riparian coniferous forests of central Idaho, USA. Specifically, we how the two types affected inorganic N concentrations, microbial biomass gross transformation rates relative to corresponding unburnt controls. There was no significant difference soil NH4+ concentrations burnt control either type fires. However, significantly reduced ammonification uptake...
Abstract A semi‐mechanistic forest growth model, 3‐ PG ( P hysiological rinciples redicting G rowth), was extended to calculate δ 13 C in tree rings. The estimates were based on the model's existing description of carbon assimilation and canopy conductance. model tested two ∼80‐year‐old natural stands bies grandis (grand fir) northern Idaho. We used as many independent measurements possible parameterize model. Measured parameters included quantum yield, specific leaf area, soil water content...
Following planting, western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings experience water stress and declining xylem pressure potential (Psi(x)). Low Psi(x) can result in cavitation embolism formation, causing a decline hydraulic conductance. This study focused on the relationship between Psi(x), transpiration (E) of newly planted seedlings. Leaf specific conductance (k(AB)) declined from 0.56 to 0.09 mmol m(-2) s(-1) MPa(-1) over 9-day period. Stomatal (g(s)) 143.5 39.15 same period...
The effects of 30 years (1972–2003) Wildland Fire Use for Resource Benefit (WFU) fires on ponderosa pine forest stand structure were evaluated in the Gila Wilderness, New Mexico, and Saguaro Arizona. Tree density, diameter-class distributions, basal area, density index compared among areas that burned with different frequencies since 1972 mid-century (1940–1950) again during WFU era (1972–2003). In both Wilderness significantly fewer small-diameter (5 cm to 22.5 cm) trees occurred multiple...
We evaluated differences in the effects of three low-severity spring prescribed burns and four wildfires on nitrogen (N) biogeochemistry Rocky Mountain headwater watersheds. compared paired (burned/unburned) watersheds for growing seasons post-fire. To better understand fire entire watershed ecosystem, we measured N concentrations δ15N both terrestrial aquatic ecosystems components, i.e., soil, understory plants upland riparian areas, streamwater, in-stream moss. In addition, nitrate...
Abstract Increasingly, land managers have attempted to use extreme prescribed fire as a method address woody plant encroachment in savanna ecosystems. The effect that these fires on herbaceous vegetation is poorly understood. We experimentally examined immediate (<24 hr) bud response of two dominant graminoids, C 3 caespitose grass, Nassella leucotricha , and 4 stoloniferous Hilaria belangeri following varying energy (J/m 2 ) semiarid the Edwards Plateau ecoregion Texas. Treatments...
Terrestrial and marine ecosystems are linked by the annual migration of salmonids. We examined contribution anadromous fish to foliar nitrogen (N) in central Idaho riparian forests where have been sharp decline for approximately 30 years. To determine if amount N from carcasses can be assessed conifer foliage, we fertilized seedlings with varying proportions sources analyzed their 15 N/ 14 ratio (δ N). Also, evaluate whether obtained was evident forests, δ above below waterfalls, along...