A5029421773- Ecology and Vegetation Dynamics Studies
- Fire effects on ecosystems
- Plant Water Relations and Carbon Dynamics
- Tree-ring climate responses
- Rangeland and Wildlife Management
- Forest ecology and management
- Soil Carbon and Nitrogen Dynamics
- Forest Ecology and Biodiversity Studies
- Plant and animal studies
- Species Distribution and Climate Change
- Atmospheric and Environmental Gas Dynamics
- Hydrology and Watershed Management Studies
- Soil erosion and sediment transport
- Landslides and related hazards
- Remote Sensing in Agriculture
- Cryospheric studies and observations
- Forest Management and Policy
- Forest Biomass Utilization and Management
- Soil and Water Nutrient Dynamics
- Climate change and permafrost
- Disaster Management and Resilience
- Groundwater flow and contamination studies
- Peatlands and Wetlands Ecology
- Geology and Paleoclimatology Research
- Hydrology and Sediment Transport Processes
Pennsylvania State University
2014-2024
Colorado State University
1999-2005
University of Arizona
1999-2001
Ecosystem Sciences
1999
Abstract Projected changes in temperature and drought regime are likely to reduce carbon (C) storage forests, thereby amplifying rates of climate change. While such reductions often presumed be greatest semi‐arid forests that experience widespread tree mortality, the consequences may also important temperate mesic Eastern North America ( ENA ) if growth is significantly curtailed by drought. Investigations environmental conditions determine sensitivity critically needed accurately predict...
Tree plantations are an important component of tropical landscapes, providing wood, fuel, and perhaps carbon (C) sequestration. Primary production in wet is typically nutrient limited. In some Hawaiian Eucalyptus plantations, nitrogen (N) limitations to alleviated by intercropping N-fixing Albizia trees that may decrease available phosphorus (P). Thus, sustainable productivity C sequestration depend on species composition. We measured soil N P availability ecosystem a 17-yr-old replicated...
AbstractTemperatures across the northern regions of North America have been increasing for 150 years, and forests responded to this increase. In Noatak National Preserve in Alaska, white spruce (Picea glauca [Moench] Voss) reach their limit, occurring primarily on well-drained sites as gallery along streams. Rolling plateaus tundra separate into disjunct stands. We examined patterns tree age, growth, encroachment ecosystems six stands Agashashok River. Warming over past years appears...
Southwestern ponderosa pine forests were dramatically altered by fire regime disruption that accompanied Euro-American settlement in the 1800s. Major changes include increased tree density, diminished herbaceous cover, and a shift from frequent low-intensity to stand-replacing regime. Ecological restoration via thinning prescribed burning is being widely applied return pre-settlement condition, but effects of on ecosystem function are unknown. We measured carbon (C), nitrogen (N), phosphorus...
Abstract Experimental study of the effects projected climate change on plant phenology allows us to isolate warming life‐history events such as leaf out. We simulated a 2 °C temperature increase and 20% precipitation in recently harvested temperate deciduous forest community central Pennsylvania, USA , observed out all species 2009 2010. Over 130 were monitored weekly plots, but due high variability composition among grouped into five functional groups: short forbs, tall shrubs, small trees,...
Climate and competition are often presented from two opposing views of the dominant driver individual tree growth species distribution in temperate forests, such as those eastern United States. Previous studies have provided abundant evidence indicating that both factors influence growth, we argue these effects not independent one another rather interactions between climate, competition, size best describe growth. To illustrate this point, responses five common to interacting temperature,...
Abstract. Many scientists have begun to refer the earth surface environment from upper canopy depths of bedrock as critical zone (CZ). Identification CZ an integral object worthy study implicitly posits that whole will provide benefits do not arise when studying individual parts. To CZ, however, requires prioritizing among measurements can be made – and we generally agree on priorities. Currently, Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) is expanding a small original focus...
In forested ecosystems, topography and tree species contribute to spatial variability in carbon (C) dynamics through differential rates of C uptake storage; therefore, estimates species-specific can strengthen ecosystem budgets. To produce such estimates, we deconstructed watershed-scale component pools (e.g., wood biomass, litter) fluxes at a fine scale using small mixed deciduous forest catchment determine the variation due topographic position species. Factors affecting included aspect,...
Core Ideas Studying the critical zone requires targeted research on water, energy, gas, solutes, and sediments. The SSHCZO targets a 165‐km 2 watershed sedimentary rocks in northeastern United States. One subcatchment, Shale Hills, provides extraordinary data describing shale CZ. Susquehanna Hills Critical Zone Observatory (SSHCZO) was established to investigate form, function, dynamics of developed Appalachian Mountains central Pennsylvania. When first established, encompassed only...
AbstractPatterning in fire regimes occurs at multiple spatiotemporal scales owing to differences scaling of local and regional influences. Local occurrence behavior may be controlled largely by site factors, while climate changes human land use can synchronize timing across large areas. We examined historical patterns fires during the past five centuries gradients forest types physiography relation variability change Sacramento Mountains southern New Mexico. Forest stand-level chronologies...
Elk browsing and conifer species mixing with aspen ( Populus tremuloides Michx.) present current challenges to forest management in the western United States. We evaluated effects of conifers elk on quaking stands near Rocky Mountain National Park using tree rings reconstruct patterns establishment, growth, mortality over past 120 years. High encroachment browse were both associated decreased recruitment, mean recruitment dropping 30% from pure mixed 50% low‐browse high‐browse stands....
Fire historians typically attribute the causes of temporal change in past fire regimes to climatic variation, human land use, or some combination two. Most long-term historical reconstructions, however, lack time and place-specific chronologies for all three variables fire, climate, people. To test hypothesis that Mescalero Apache southeastern New Mexico influenced Sacramento Mountains, we reconstructed compared key period A.D. 1700 present. Fire-scarred trees were used reconstruct...
Experimental study of the effects projected climate change on plant phenology allows us to isolate warming life-history events such as leaf out. We simulated a 2 °C temperature increase and 20% precipitation in recently harvested temperate deciduous forest community central Pennsylvania, USA, observed out all species 2009 2010. Over 130 were monitored weekly plots, but due high variability composition among grouped into five functional groups: short forbs, tall shrubs, small trees, large...
Dendroecology is the science that dates tree rings to their exact calendar year of formation study processes influence forest ecology (e.g., Speer 2010 [1], Amoroso et al., 2017 [2]) [...]
Core Ideas Two new subcatchments are used to test the importance of lithology and land use. Differences in use result differences soils waters. Despite differences, all catchments have a shallow deep water table. The relative flow paths controls distinct chemistry response discharge. Cross‐site comparison will ultimately enable upscaling from catchment large scale. footprint Susquehanna Shale Hills Critical Zone Observatory was expanded 2013 forested subcatchment (0.08 km 2 ) most Shavers...
Abstract In eastern deciduous forests of North America, invasive shrubs are increasing in richness and abundance at the expense native species across taxa. Invasive create an understory that is more dense than both recent historical preinvasion conditions. Interest shrub removal to restore habitat growing, but our understanding natural regeneration following treatment a diverse community lagging. Using experiment, we provide insight into effect repeated suite 18 dominated by border privet (...