Data from flux sites help test physiological models of carbon exchange and are critical to relating fluxes and remote sensing data. Companion physiological and ecological measurements enable partitioning carbon fluxes into plant and soil components and reveal mechanisms responsible for these fluxes. Data from the flux sites have been applied in ecology, weather forecasting, and climate studies, especially for sites with several years of data to quantify inter-annual flux variations.
Studies on carbon dioxide concentration, CO2 and H2O flux, and the effects of multiple air pollutants on urban forests are being conducted in Baltimore. Urban conditions may represent possible future scenarios: elevated carbon dioxide, ozone, nitrogen deposition and elevated temperatures. A 40 m Forest Service lookout tower near Baltimore is used to conduct air quality and meteorological flux research. This is the first permanent tower to estimate carbon flux and carbon sequestration in an urban/suburban forest ecosystem. Metropolitan areas have an average tree cover of 33.4% (urban counties) and support 25% of the USA's total tree canopy cover, and their inclusion in climate models is essential for accuracy.
Acid rain and other anthropogenic factors can leach calcium (Ca) from forest ecosystems and mobilize potentially toxic aluminum (Al) in soils. Considering the unique role Ca plays in the physiological response of cells to environmental stress, we propose that depletion of biological Ca would impair basic stress recognition and response systems, and predispose trees to exaggerated injury following exposure to other environmental stresses.
Young communities of trembling aspen (Populus tremuloides) have been grown under elevated concentrations of carbon dioxide and elevated ozone at the Aspen FACE site, Harshaw, WI. We are using microsatellite markers to generate distinct DNA fingerprints for each of the five-aspen clones. These DNA fingerprints will be used to quantify fine-root biomass, in particular to monitor changes that occur when trees are exposed to atmospheric pollutants.
Methods are needed to assess the positive or negative impact of environmental pollution on forest productivity in an asymptomatic forest stand. A goal of several research groups in the Northern Research Station (NRS) is to develop a set of physiological and biochemical markers that can assess the early onset of stress in forests due to environmental factors, before injury is visible.
Land managers need specific information, strategies, and tools to address the unique challenges of managing forests under uncertain and changing climate and ecosystem response. Sustainable forest management is critical for both the adaptation of forests to changing climatic conditions as well as mitigation of increased levels of atmospheric greenhouse gases. The uncertainty of future climatic conditions necessitates adaptive techniques and strategies that provide flexibility and enhance ecosystem resistance and resilience. This project laid the foundation for what is now the Climate Change Response Framework, in addition to several other projects.
The success of forest regeneration programs depends upon the development of adaptation strategies for ecosystem sustainability under changing climates. There is a need to identify tree species and seed sources with enhanced adaptation to climate change pressures to ensure biologically and economically sustainable reforestation, afforestation, and gene conservation.
In 1998 the USDA Forest Service, the U.S. Geological Survey, and the National Park Service formed the Collaborative Environmental Monitoring and Research Initiative (CEMRI) to test strategies for integrated environmental monitoring among the agencies. The CEMRI project illustrates a powerful approach for tracking of environmental conditions, development of models for predicting responses of forest and aquatic processes to perturbations, estimation of future forest conditions, and identification of threats to watershed health and forest sustainability.
Managers often need frequent, updated assessments of current and developing conditions on which to base management decisions and respond to public concerns. No methodology has been developed to indicate when a forest population is at risk to specific local and regional climate and air pollution stressors. This study resulted in an on-line information system featuring data on the relationships among various regional and global climate forcing factors and the health of forests in the north central and northeastern US, as measured by forest dieback.
Understanding the spatial and temporal patterns of climate variables throughout the region is important in developing effective land management strategies that can sustain our natural resources. This effort is helping to identify when and where climate and weather related disturbances typically occur in the north central and northeastern U.S.