Money can grow on trees! The ability to compare the value of natural lands to developed lands was historically difficult until the concept of "environmental services" was developed. Environmental services include things such as: clean air, clean water, aesthetics, and non-timber forest products. Complex models have been created to estimate the monetary value of these products and services. Another way to look at it is: how much would it cost technology to replicate the services that trees provide naturally?
By placing a monetary value on environmental services, different land uses can be compared apples to apples. For example, a 2007 study determined that Tampa’s urban forests removed approximately 1,360 tons of air pollution with an estimated value of $6.4 million.
Casey Trees and Davey Tree Expert Co. developed The National Tree Benefit Calculator to help determine the monetary value of the very trees that exist in our backyard. Using this calculator, the overall benefits of a 36 inch (diameter) live oak tree in a single-family residential neighborhood of Clearwater, FL was determined to be worth $303 every year. Benefits are broken down into different categories including: stormwater, property value, energy, air quality, and carbon dioxide (CO2).
Human development can increase impervious surfaces such as concrete and asphalt that do not allow water to seep through the surface. Instead, these surfaces force water to “runoff” until it reaches soils where it can percolate into the groundwater or enter into streams, wetlands, rivers or oceans. Trees help increase the infiltration rate and storage of rainwater through the tree’s root system. Using the same 36 inch diameter live oak, approximately 28,552 gallons of stormwater runoff would be intercepted by this tree every year.
Trees can also help increase property value. Research shows that home buyers are willing to pay higher prices for properties with more trees compared to properties with few to none. The live oak from our example, if located in the front of a single family home, was estimated to increase property value by $173.
Shade of trees can save money too. Trees that shade the east and west walls of a building in the summer help to keep the building cooler. Also, by leaving the southern side of a building exposed during the winter months it can help warm interior spaces. Our 36 inch diameter live oak would conserve 246 kilowatt hours of electricity per year for cooling, which equals $15.44 (based on 6.28 cents per Kilowatt hour).
Improved air quality can be another benefit of trees and shrubs by absorbing pollutants such as sulfur dioxide and help to reduce the amount of carbon dioxide in the atmosphere. Our sample tree is capable of reducing atmospheric carbon by 2,276 pounds. To put this into perspective, a flight from New York to Los Angeles adds 1,400 pounds of CO2 per passenger.
In summary, urban trees are beneficial in a variety of ways. Try calculating some of the trees in your yard using the online calculator. If you want to learn how to identify some of the trees in your yard, register for the upcoming Adult Ecology: Plant ID Series offered at Brooker Creek Preserve. Follow what’s going on with natural resources around
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