With an increasingly growing urban population and urban sprawl, maintaining the natural resources in these communities becomes critically important. The urban population has ballooned from 28% in 1910 to 80% in 2000 (U.S. Census Bureau, 2002) and with it the need for natural resources management to ensure sustainable development, enhance the quality of life and maintain the health and balance of the environment. Sometimes there can be difficulty in evaluating the costs and benefits to preserving and protecting the urban canopy, however, ecological, social and aesthetic benefits are, for the most part, quantifiable.
Trees provide 5 distinct environmental benefits:1) carbon sequestration, 2) stormwater management, 3) air pollution reduction, 4) decreased energy usage and 5) water quality improvement. Trees help reduce air pollution by trapping particulate pollutants in crown vegetation and absorbing noxious components into leaves. Eventually particulate matter will be washed away with rain and absorbed pollutants will be returned to the soil through decomposition. In this way, trees are almost shielding the human community from receiving these pollutants. Tree canopies and root systems also intercept and slow down large amounts of precipitation which helps manage runoff, reduces flooding and stems erosion. The biomass of the urban canopy absorbs and stores carbon, locking it into the nutrient cycle, keeping it out of the atmosphere and hydrocycle. This sequestration of carbon eliminates it from contributing greenhouse gases into the atmosphere. Additionally, trees absorb and uptake nutrients from the soil, a lot of which may have ended up as runoff into the watershed which can cause algal blooms and harm aquatic life. Canopy cover can also help reduce energy usage and costs by providing shade and transpiring cooling water vapor.
While social benefits are somewhat more difficult to quantify they are equally as important as environmental benefits. Studies have shown that sufficient tree and vegetation cover improves peoples’ feelings of job satisfaction, increases the speed of recovery for hospital patients and improves early childhood development. Patients and employees with views of nature and/or trees from their rooms or workstations recovered faster and more effectively and were happier and more efficient at work, respectively. Both of these scenarios are translatable into dollar values, if not exact amounts, such as; lower healthcare costs and higher workplace productivity. Without trees outdoor recreation opportunities such as hiking, camping, fishing, picnicking or just having a cookout in your yard are much less enjoyable, some even impossible. Finally, but certainly not of least importance, trees provide habitat and forage for a wide range of dependent wildlife.
Aesthetic values can of trees and vegetation can be measured by the increase in property value when trees and landscaping is added. Property values have been known to rise up to 20%, depending on other regional metrics, when trees are present. Professional tree appraisers can evaluate the monetary contribution of a tree by examining the landscape, size, species, condition and location of said specimen. Appraisals of tree value are often made to help determine how much a homeowner is due if damage or vandalization occurs on his property.
Help conserve and protect trees in your community and add value to society, improve the environment and increase property values. Maintaining your trees’ health through a properly developed nutrition, pest and disease management program designed by your arborist can be a good first step. You can also make a difference by attending and contributing to urban and community planning programs and/or volunteering in your local garden group.
Kane, Brian and Kirwin, Jeff “Value, Benefits, and Costs of Urban Trees”, Virginia Technical University Publications and Educational Resources, 2009: 420-181