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You are here: NRS Home / Research Programs / Clean Air and Water / Methods to Conserve and Enhance the Production of Clean Water from Forests
Clean Air and Water

Methods to Conserve and Enhance the Production of Clean Water from Forests

Stream-side forests are crucial to the protection and enhancement of water resources. They are extremely complex ecosystems that provide useful ecosystem service in mitigating or controlling non-point-source pollution as well as providing optimum food and habitat for stream communities. As a component of an integrated management system including nutrient management and sediment and erosion control practices, stream-side forests have important effects on water quality. They remove excess nutrients and pollutants (that is, fertilizers and some pesticides) and sediments from surface runoff and shallow groundwater and they also shade streams to optimize light and temperature conditions and provide dissolved and particulate organic food for aquatic plants and animals.

Selected Research Studies

photo:] Prairie strip embedded in an agricultural (corn) watershed.  The prairie strips increase nutrient and sediment retention, reduce runoff, and increase biodiversity.  Photo Credit: Iowa State University..Environmental Health and Community Vitality in Agricultural Landscapes
Reducing sediment and nutrient export from agricultural landscapes is critical to decreasing nonpoint-source pollution in water systems in the Cornbelt region of the United States, where intensively managed rowcrop systems dominate the landscape. 

There is a growing recognition that intensive row crop agriculture as currently practiced in the Upper Midwest lacks both ecological resilience and socioeconomic sustainability.


[photo:] Mapping the locations of sediment sources and associated hillside characteristics.  These data are used in mathematical models to determine factors that influence sediment transport to streams. Sediment Delivery and Best Management Practices
Soil is eroded and delivered naturally to streams and rivers by rainfall, gravity, and other processes, and these inputs are important for maintaining healthy channel conditions.  Human-caused, elevated inputs can be detrimental to water bodies because they can affect water quality, fish reproduction and survival, channel stability, and flooding potential.  Understanding the processes that control natural and human-induced erosion and sedimentation is essential for maintaining water quality and stream health, and for improving the effectiveness of forest practices used to limit water pollution (i.e., best management practices, or BMPs).  


[photo:] stream in forest at high flow, showing the clean water that is a hallmark of forested watershedsWater from Forests
Because the majority of the U.S. drinking water supplies originate on forested land, forest managers must be able to predict the effects of their management activities upon the quantity and quality of water coming from these forests.  Thus, a sound understanding of the effects of disturbances, both natural and human-caused, on water quality and quantity is needed to help sustain healthy forests and clean abundant water, in  a world with changing climate.


[Image] Graph of N and S deposition.  X-Axis: N Deposition, Y-Axis: S Deposition.  flat line and then a 45 degree angle downCritical Loads Resources for Federal Land Managers
The critical load is scientifically determined based on expected ecosystem response to a given deposition level.  The target load is set by policy makers, land managers, or air regulators to protect sensitive ecosystem components.  The target load may be higher or lower than the critical load, and is based on the economic cost of emissions reductions, timeframe, and other considerations.

This website contains documents and information useful to Federal Land Managers and others for understanding calculations of critical loads for nitrogen and sulfur deposition to forest ecosystems in theory and practice.


[image:] Map of predicted losses of nitrogen from forested lands of the Chesapeake Bay watershed under no nitrogen deposition, current nitrogen deposition, and doubled nitrogen deposition (Pan et al. 2004).Mid-Atlantic Forests and the Chesapeake Bay Watershed
Forest landscapes are changing as a consequence of climate and environmental change. These changes affect people and the forest ecosystems they depend on for clean water, clean air and forest products, and recreation. How can we best manage our forest resources to sustain this array of ecosystem services under increasing environmental stress and a changing climate?


[photo:] Delaware River basinThe Delaware River Basin: Collaborative Environmental Research and Monitoring
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 initiative combined monitoring and research efforts of the participating Federal programs to evaluate health and sustainability of forest and freshwater aquatic systems in the Delaware River Basin. 


[photo:] Watershed 3, Fernow Experimental Forest.  Treated watershed for the Fernow Watershed Acidification Study, started in 1989, one of only 2 whole-water acidification studies in the U.S. Air Pollution and Sustainable Forest Ecosystems
In our research, we monitor acidic deposition falling in the central Appalachians and study its effects as its moves through the forest, from tree canopy to the soil and soil solution to streams.  We are studying the effects on nutrient cycling, and tree growth and productivity, and on a number of other ecosystem components. 


[photo:] Two-year-old poplar root system following harvesting of a field testing cycle during phyto-recurrent selection.Phyto-Recurrent Selection: A Method for Selecting Genotypes for Phytotechnologies
The success of certain phytotechnologies has prompted the use of wastewaters as a combination of irrigation and fertilization for woody crops such Populus species and their hybrids (i.e., poplars). A common protocol for such efforts has been to utilize a limited number of readily-available genotypes with decades of deployment in other applications, such as fiber or windbreaks. However, it is possible to increase phytoremediation success with proper genotypic screening and selection, followed by the field establishment of clones that exhibited favorable potential for clean-up of specific contaminants. While such efforts are limited for environmental remediation, centuries of plant selection success in agronomy, horticulture, and forestry validate the need for similar approaches in phytotechnologies. 


[photo:] Shortleaf pine commonly grows with hardwoods in the Missouri Ozarks and elsewhere in the Central Hardwood Region.  Management of pine with hardwoods in natural stands is a new line of research to develop silvicultural systems for regenerating pine and sustaining it in forest and woodland systems.Agroforestry Practices for Biodiversity Conservation
Agroforestry in the temperate region is the intentional integration of trees and shrubs with livestock or crops into intensive land management systems. It can include practices such as alley-cropping, silvopastural, and riparian buffers. Integrating woody vegetation with grasses and forbs provides a wider range of habitats than would typically be found in most agricultural systems and can also enhance the production of clean water.


[image:]  Pond surrounded by treesCarbon Cycling Research at Silas Little Experimental Forest
An understanding of carbon, water, and energy exchanges between forests and the atmosphere at multiple scales in time and space is necessary to better inform decisions that are made concerning forest management, carbon sequestration, fire management, and the climate system.


[image:] Map of predicted losses of nitrogen from forested lands of the Chesapeake Bay watershed under no nitrogen deposition, current nitrogen deposition, and doubled nitrogen deposition (Pan et al. 2004).Mid-Atlantic Forests and the Chesapeake Bay Watershed
Forest landscapes are changing as a consequence of climate and environmental change. These changes affect people and the forest ecosystems they depend on for clean water, clean air and forest products, and recreation. How can we best manage our forest resources to sustain this array of ecosystem services under increasing environmental stress and a changing climate?


[photo:] Poplar planted in soils heavily contaminated with petroleum hydrocarbons. Salt Tolerance and Salinity Thresholds of Woody Energy Crops Irrigated with High-salinity Waste Waters
There is a need for environmental practices that merge intensive forestry with waste management. Producing short rotation woody crops for energy, fiber, and environmental benefits requires adequate irrigation and fertilization, which can be supplied via waste waters including landfill leachate. Yet, leachate often contains elevated levels of salts such as chloride and sodium that cause leaf chlorosis and necrosis, decreased biomass accumulation, and increased mortality. Therefore, there is a pressing need to learn about the response of poplar energy crops when salts are taken up into root, leaf, and woody (stem + branch) tissues, as well as identifying thresholds of salt concentrations and salinity that can be recommended for these crops in both field testing and production plantations.


[photo:] Poplar planted in soils heavily contaminated with petroleum hydrocarbons. Using Short Rotation Woody Crops to Remediate Soils Heavily Contaminated with Petroleum Hydrocarbons
Organic contaminants such as petroleum hydrocarbons are a major pollution source of surface water, groundwater, soil, and sediments throughout North America and the rest of the world. The rhizosphere is the zone of soil surrounding plant roots. Utilization of plants and their rhizospheric microorganisms to destroy, remove, and stabilize contaminated soils is currently gaining global attention because such systems are efficient and effective from biological and economic standpoints.


[photo:] Poplar energy crops grown for biomass and used for waste water reuse and recycling. Sustainable Production of Woody Energy Crops with Associated Environmental Benefits
Increasing human population levels at regional, national, and global scales have heightened the need for proper management of residential and industrial waste. Contaminants from this waste stream have polluted water, air, and soil much faster than traditional technologies could remediate the problem. Therefore, we are combining intensive forestry and waste management methods to increase the potential for producing woody crops for energy and fiber, along with decreasing the environmental degradation associated with waste disposal and subsequent waste water production.


Photo: Hubbard Brook Experimental ForestThe Northeast Decision Model
The Northern Station is deeply committed to developing the Northeast Decision Model, a PC-based model designed to aid forest managers in selecting appropriate management practices. The model utilizes knowledge about a variety of ecosystem services, including water, wildlife, and aesthetics. Long-term data and knowledge about water resources obtained from the Hubbard Brook Ecosystem Study (HBES) is critical to the decision model. In addition, these scientists are preparing a stand-alone decision model dedicated to water resources in the 20-state area of Northeastern Area State and Private Forestry. This model enables forest and aquatic managers to choose from a variety of water yield and water quality goals and provide them with management recommendations.


Photo: Fish swims near river bottomAcid deposition and aquatic ecosystems
Many aquatic ecosystems in the Northeast are affected by acidic deposition from industrial pollution, primarily in the areas with thin soils overlaying granite rock. As base cations become depleted from these soils and they become less alkaline, there is less buffering capacity to counteract the acid deposition and ultimately, increased amounts of aluminum are leached into streams and lakes. Nitrogen saturation of soils will further acidify streamwaters and affect other aspects of the water’s chemical and biological quality and human safety. NRS scientists are studying the linkages between terrestrial and aquatic ecosystems to provide better information on the long-term impacts of acidic deposition.


PhotoClearcutting and watershed flow
Watershed-level evaluations of forest management options (such as clearcutting) and modeling of storm water data show the relation between open or young forest land and increases and decreases in streamflow rates. These data have been translated to harvest-rate and open land guides for various national forest plans, state forest plans, and county forest plans as well as river-basin planning groups in the Lake States.


Photo: Weir at Hubbard Brook Experimental ForestMercury and water pollution
NRS scientists are assessing nutrient (nitrogen and phosphorus), carbon, and mercury pools and processes in a variety of ecosystems, including forests, riparian and wetland systems, peatlands, and agricultural watersheds. Ecosystem carbon work extends into characterizing the pools of coarse woody debris in forested riparian areas and streams. This mercury work is focused on two main efforts, one to characterize the mercury cycle under increased sulfate deposition and a second to understand the influence of prescribed fire on mercury cycling.


Photo: Installation of recording well in Marcell Experimental ForestGroundwater-wells on the Marcell Experimental Forest (MEF)
MEF incorporates an extensive and long-term evaluation of groundwater wells. These data are used in combination with paleo-botanical studies of peat profiles, and soil hydraulic conductivity to illustrate the significance of deep seepage to water and nutrient budgets on experimental watersheds. The MEF along with (now) some 200 sites in the United States has documented the chemistry of precipitation and trends in atmospheric deposition in the United States for the last 25 years. Currently, the MEF has built 8 years of mercury deposition data and has contributed to the evaluation of methane as a greenhouse gas and its potential effects on global warming processes.


Last Modified: 03/06/2013