Urban forests are more than just trees
John Wear explains their benefits to humanity.
Salazar: Thank you for speaking with me today, Dr. Wear. Would you define an ‘urban forest’ for me? How does an urban forest look?
Wear: It depends on who you ask. In the minds of some, an urban forest is the aggregate of all vegetation and green spaces within a community. In others, it’s more defined.
In our case, here at Catawaba College, we have an 187–acre ecological preserve that we consider part of the urban forest system here in the city of Salisbury. What makes it unique is that it’s right in the middle of an urban environment, yet is very natural, with over 150 different species of birds, numerous other types of wildlife, including beavers that now dam much of the water up.
In this particular urban forest, we have native vegetation. In other portions of the community that one would also consider part of the urban forest system, you might have a greenway with planted trees that are more exotic varieties.
But it doesn’t matter whether they’re native species in an ecological preserve, or planted species on a greenway system, or street trees throughout the community. All of them provide ecosystem services in terms of removal of pollutants, the protection of our water quality, and in many cases, providing a habitat for wildlife.
Salazar: You mentioned ecosystem services; would you elaborate a bit on what those are and why they’re important?
Wear: There are a lot of different ways of looking at the ecological services provided by our forests and our tree canopies, protecting our environment and improving air quality, water quality, and providing a habitat for animals. We have to consider all of these things when we think about why we need to preserve urban forests in a community and especially setting aside natural areas as we develop. All of these become important.
Often these services they provide are not integrated into the real planning processes for a community. In other words, what are the economic and health–related services that are provided by a forest within a community, or a tree canopy within a community? How do you calculate that, and of what importance is that? Often, that is not calculated at all in the planning process or in the development of a community, and it is a very important aspect that can be calculated.
For instance, if we remove a forested area in a watershed, what impact is that going to have on our water quality? Because it is going to have an impact. If we remove a portion of a forest, what impact is it going to have in terms of reduction on the natural filtering of air, in terms of things like nitrogen oxides, and ozone, or sulfur dioxide, or carbon dioxide? These factors are often not calculated into the thinking in terms of planning how we develop a community. And we’re really at the point where these need to be, without question, calculated in.
Salazar: What kind of urban forest is best for the ecosystem?
Wear: If we look at the services provided by an urban ecosystem, or urban forest all over the city, the greater the tree cover and the less the impervious surface in a community, the more ecosystem services are produced. These services are measured as storm water runoff reduction, increased air and water quality, carbon storage, and energy reduction.
In a study done by American Forests, in conjunction with the Center for the Environment, they looked at the real benefits and tried to put numbers to those benefits. For instance, with this 187–acre ecological preserve, which has about a 75% coverage in trees, the ozone reduction in pounds removed per year, is approximately 5,702 pounds per year. Nitrogen dioxide, which is a precursor to ozone, would be 1,240 pounds. So, there we can see the immediate benefits in terms of the particular air quality types of problems that we’re having in this community. Particulate matter, for instance, 4,958 pounds of particulate matter would be removed from the atmosphere through this forest system.
As we see the effects of climate change, it becomes especially important to think in terms of the tree canopy cover for a community and preserving certain habitats within a community, so that they can function in a number of ways, including reducing the effects of global climate change by sequestering carbon dioxide emissions. And in this particular preserve, we would see the removal of approximately 47 tons of carbon storage that is going in this preserve, annually. In other words, the preserve is sequestering 47 tons on an annual basis of carbon and storing approximately 5,980 tons of carbon at all times. So that’s pretty important to consider.
Salazar: Thank you for taking time to speak with me today.
“Dr. John E. Wear Jr.”:http://www.catawba.edu/academic/environmentalscience/faculty.htm is the founding director of the Catawba College Center for the Environment, located near Salisbury, North Carolina. Wear established the Center and launched Catawba’s Environmental Science & Environmental Studies Program in 1993. Dr. Wear has committed his energies to environmental initiatives at the local, regional and state level. His leadership was instrumental in launching the Clean Air Initiative for Rowan and the Central Piedmont, as well as helping to establish the South Yadkin Wildlife refuge. He was named the 2003 N.C. Conservationist of the Year by the Governor’s Conservation Achievement Awards Program; a 2002 Guardian of the Earth by The Charlotte Observer; and the 2001 Recycler of the Year by the Carolina Recycling Association (the nation’s largest recycling organization).
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