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Trees
– The Mainstay of our Green Infrastructure
When considering capital assets in our cities and suburbs, we would immediately list roads, water, sewer, sidewalks, public buildings and recreational facilities. These facilities are part of our community’s infrastructure, paid for with tax dollars to serve our families and businesses. We might not think of trees when making our list, but they represent a “green infrastructure” that provides benefits and services of incalculable value. Here in the Upstate we are blessed with good ecological conditions for growing trees, and – until recently – we have taken our ample tree canopy for granted. However, we are now losing trees at an alarming rate – 40 acres of the Upstate’s landscape is developed every single day, and in many cases land is cleared of all vegetation before construction begins. Only a short distance down the road you can see firsthand the consequences another area has suffered because they failed to protect their tree cover. The Atlanta region has lost massive amounts of its tree cover, and the loss continues at a rate of 50 acres per day – a major cause of an 8 to 10 degree increase in temperature in and around the city.1 Not only does the excess heat place higher demands on cooling systems in cars and buildings, it also causes changes in local weather patterns such as increasing the incidence of thunderstorms. In addition, heat accelerates the formation of ozone, a destructive type of smog that interferes with the process of photosynthesis and damages the lung tissue of humans and other animals. The hotter it is, the more ozone is formed. Air and Water Quality A tree is one of nature’s most efficient recycling machines. Trees convert carbon dioxide (CO2) to breathable oxygen. In the process, they sequester the carbon in their woody tissue and roots until the tree dies and slowly releases it back into the atmosphere to be reused by other organisms. In addition, trees remove pollutants from the air like ozone and particulate matter, and help cool the air through transpiration and shading. Trees also play an important role in securing and purifying water supplies for communities. By intercepting rainwater with their leaves, branches, and trunks, trees reduce stormwater runoff, thereby lessening the need for human-engineered facilities like retention ponds and drainage systems. This, in turn, keeps soil moist and groundwater replenished. In addition, trees help absorb pollutants like nitrates, phosphorus and potassium and use them as food. Many of these environmental benefits have been quantified. One study found that Atlanta’s heavy decline in tree cover has resulted in a 33 per cent increase in stormwater runoff; retaining this increase requires stormwater facilities at a cost of approximately $1.18 billion.(2) In another study, the U.S. Forest Service reports that during a 50-year lifespan, one tree will generate $30,000 in oxygen, recycle $35,000 worth of water, and clean up $60,000 worth of air pollution, which comes to a total of $125,000, not to mention its many other benefits.(3) Economic Benefits
Trees
are “green” in more than one way – they provide
enormous economic benefits to society. When given the choice between
a home or office without trees and a similar structure with trees,
many Americans are willing to pay more for the latter. One study
found that for homes in Athens, Georgia, landscaping with trees
was associated with a 3.5 to 4.5 per cent increase in the sales
price.(4) In another area,
rental rates for office buildings with landscaping and trees were
responsible for an increase in office rental rates of Trees in business districts attract shoppers who will drive farther, stay longer, and visit more frequently than in treeless areas. Research suggests that “healthy and well-maintained trees send positive messages about the appeal of a district, the quality of products there, and what customer service a shopper can expect.”(6) Policies for Protecting Trees In response to the increasing rate of development and rapid tree loss, many South Carolina cities and counties have adopted policies to ensure adequate and healthy tree cover in their communities. According to a 2003 study conducted by the Strom Thurmond Institute, at least 81 municipalities and 22 counties have adopted at least one type of ordinance that sets minimum standards for the protection of certain trees or for the planting of new trees in commercial and residential developments or in parking lots.(7)
In general, tree regulations are adopted most often in larger and growing communities in South Carolina.(8) In the Upstate, the cities of Greenville, Greer and Spartanburg have regulations that provide protection for existing trees to some degree, and – along with these three cities – at least 10 other Upstate cities have landscaping or street tree requirements. However, even though 90 per cent of the region’s development is occurring in unincorporated areas,(9) no county has yet adopted comprehensive tree protection, while four have only landscaping standards for bufferyards and/or parking lots. (Anderson County encourages but does not require the retention of trees in developments.) The best and perhaps only truly effective way to ensure adequate and healthy tree cover is by adopting countywide tree ordinances in every county. Such a policy would set minimum standards for the number of trees that are required in all developments and for the size and type of trees that must be protected outright. In addition to minimum standards, incentives could be used to encourage retention or replanting of more than what is required. So, the next time you’re in your car and a beautiful tree catches your eye, think about it as part of our area’s infrastructure – no less important than the road you’re on. And call your County Council member to say that it’s time to establish a tree ordinance in your county!
1
NASA, http://svs.gsfc.nasa.gov/stories/Landsat/atlanta_heat_background.html |
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