Many people may not realize it, but forests—including family forests—provide a variety of benefits related to the regulation of natural processes. For example, forests are involved in influencing weather patterns, controlling the flow of water, and reducing impacts of natural disasters.
Forests provide the following natural process regulation services (adapted from Millennium Ecosystem Assessment 2005):
- Air quality regulation. Trees help reduce pollution. Plants filter air when they take it into their leaves for photosynthesis or respiration (Smith 1990). Also, some airborne pollution particles may stick to leaves and then wash off in the rain. Although trees also give off some chemicals that can produce the ozone in smog, the overall impact on air quality depends on species, location, temperature, and other factors (Nowak 2004) but usually is considered positive.
- Macroclimate regulation. Trees absorb carbon dioxide and keep it out of the atmosphere, where it would contribute to the warming of the planet. Also, forests may influence rainfall patterns.
- Microclimate regulation. At the small-scale level, trees may buffer against extremes in temperatures. Shade and evaporation lower temperatures in summer months and create a blanket-like effect that can reduce the incidence of frost in the winter.
- Water flow regulation. Forest areas intercept water from the largest storms and release this water over time. This process leads to streams that have a less flashy flow—that is, they have water levels that rise and fall less rapidly.
- Water filtration. Water is slowed as it seeps into the forest soil, where microorganisms break down waste and pollution. Forests provide a good environment for these microorganisms.
- Erosion control. The existence of trees and other plants creates numerous effects that reduce soil erosion. Tree leaves catch and hold raindrops, reducing the speed at which the drops hit the soil surface and dislodge soil particles. Roots hold soil in place. Roots and stems slow down surface water, making it more likely to soak into the soil and less likely to carry away soil particles. Finally, roots can stabilize stream banks.
- Improvement of human health. The existence of trees and forests affects human health in direct and indirect ways (Colfer et al. 2006). The presence of trees has been linked to reduced stress and better mental health. Moreover, forests contribute to disease prevention. Many diseases are spread by contaminated water, the amount of which may be reduced by forests’ role in water filtration. The variety of living things in forests provides preferred hosts and organisms that counteract diseases, lessening the likelihood that disease-related organisms will move to human or domestic animal hosts. For instance, bats and frogs living in natural areas eat mosquitoes (Epstein 1997). It is also important to note that certain diseases are linked to forested areas, such as those carried by mosquitoes or ticks that live in forests. Usually, however, the spread of these diseases is caused not by the presence of forests but by deforestation and other human changes to the natural environment (Colfer et al. 2006).
- Pest regulation. Forests provide habitat for animals, such as brown bats, that eat insects and other pests.
- Pollination. Forests provide habitat for bees, butterflies, and other pollinators.
- Natural disaster mitigation. Strategically located forests can reduce the force of wind and water in areas that frequently are hit by storms, floods, and so on.
A group of researchers estimated the economic value of several natural process regulation ecosystem services (Costanza et al. 1994). The researchers found that temperate forests provide $36 per acre per year in climate regulation, $35 per acre per year in waste treatment, and $2 per acre per year in pest/disease control.
Water quality is one of the most valuable benefits provided by the regulating services of forests. One study showed that every 10 percent increase in forest cover in a watershed reduces the cost of treating water for human consumption by about 20 percent (Ernst et al. 2004). New York City capitalizes on this ecosystem service by paying landowners in the Catskills $150 million per year to protect forests within its watershed rather than building a new water treatment facility that would cost up to $6 billion up front and $300 million per year to operate (Postel and Thompson 2005). Water quality also affects aquatic wildlife and fishing industries. The avoidance or removal of nitrogen in the tributaries of the Mississippi River may be worth $10 to $45 per pound (Ribaudo et al. 2005); lowland forests in associated geographic areas may remove 63 pounds of nitrogen per acre per year (Murray et al. 2009).
Additionally, researchers have estimated that various forest species have substantial positive impacts on the economy. For instance, little brown bats provide pest control worth an estimated $23 billion dollars per year to the agricultural economy (Boyles et al. 2011). The value of pollination in the United States is estimated at $219 billion per year (Hein 2009). A significant portion of this ecosystem service is provided by wild insects that live in forest habitat.
It is clear that forests contribute directly and indirectly to the economy and to human well-being in many ways that do not involve buying and selling in the marketplace. Family forest landowners directly contribute to these benefits.
The following articles provide more information about the relationship of ecosystem services to family forests:
- Ecosystem Services from Family Forests
- Provisioning Ecosystem Services
- Cultural Ecosystem Services
- Programs and Policies to Pay Landowners for Ecosystem Services
Greg Frey, Virginia State University
Boyles, J.G., P.M. Cryan, G.F. McCracken, and T.H. Kunz. 2011. Economic importance of bats in agriculture. Science 332: 41-42.
Colfer, C.J.P., D. Sheil, and M. Kishi. 2006. Forests and human health: assessing the evidence. Center for International Forestry Research (CIFOR), Occasional Paper No. 45. Bogor, Indonesia.
Costanza, R., R. d’Arge, R. de Groot, S. Farber, M. Grasso, B. Hannon, K. Limburg, S. Naeem, R.V. O’Neill, J. Paruelo, R.G. Raskin, P. Sutton, and M. van den Belt. 1994. The value of the world’s ecosystem services and natural capital. Nature 387: 253-260.
Epstein, P.R. 1997 Climate, Ecology and Human Health. Consequences: The Nature and Implications of Environmental Change 3(2).
Ernst, C., R. Gullick, and K. Nixon. 2004. Protecting the source: Conserving forests to protect water. American Water Works Association. Opflow 30(5): 1, 4-7.
Hein, L. 2009. The economic value of the pollination service, a review across scales. Open Ecology Journal 2: 74-82.
Millennium Ecosystem Assessment. 2005. Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC.
Murray, B., A. Jenkins, R. Kramer, and S.P. Faulkner. 2009. Valuing ecosystem services from wetlands restoration in the Mississippi Alluvial Valley. Nicholas Institute for Environmental Policy Solutions, Duke University. Ecosystem Services Series NI R 09-02.
Nowak, D.J. 2004. The effects of urban trees on air quality. USDA Forest Service, Northern Research Station, Syracuse, NY.
Postel, S.L. and B.H. Thompson, Jr. 2005. Watershed protection: Capturing the benefits of nature’s water supply services. Natural Resources Forum 29: 98-108.
Ribaudo, M.O., R. Heimlich, and M. Peters. 2005. Nitrogen sources and Gulf hypoxia: Potential for environmental credit trading. Ecological Economics 52: 159-168.
Smith, W. H. 1990. Air Pollution and Forests. Springer-Verlag, New York.