By Steven Krolak
(NEW ALBANY, Ind.)–Clarksville is hot.
With its preponderance of built-up areas, including shopping malls, streets, interstate freeways and parking lots, the city is 4.8 degrees F hotter in the summer than it should be–a textbook heat island.
According to the U.S. Environmental Protection Agency (EPA), heat islands are defined as areas where the urban infrastructure absorbs and re-emits more of the sun’s heat than nearby natural landscapes such as forests and bodies of water.
The heat island effect reduces quality of life, with impacts ranging from increased energy consumption and elevated air pollution to compromised human health and impaired water quality.
To change this dynamic within its own borders, the Town of Clarksville developed an ordinance last spring to expand tree planting throughout the municipality.
For expert recommendations on which trees to plant or not to plant, the Planning Office reached out to Dr. David Taylor, professor of biology and professor of sustainability and regeneration.
Brandi Roads, a senior (now graduated) from Mooresville, Indiana majoring in sustainability and regeneration, took on the project as the internship which is required in the program. In September, her report with recommendations was adopted as a vital part of implementing the final ordinance passed by the Clarksville Town Council.
Growing up camping and boating, Roads had a lifelong love of the outdoors. But it was the environmental biology courses of Dr. Randy Hunt that convinced her to turn this love into a career path, becoming one of the first students to receive a degree in IU Southeast’s new Sustainability and Regeneration program.
Taylor was impressed with her interest in plants and the wider environment, so connecting her with the Clarksville initiative was a simple choice.
“Her success in both class and ability to do literature-based research on a project made her the best candidate,” Taylor said.
Some of that research bore directly on the issues involved in Clarksville. With Taylor as faculty advisor, her senior senior group research project involved a study measuring and comparing the albedo–the amount of heat projected–of different surfaces, including sidewalks, parking lots, streets, grass and wooded areas. The project also made recommendations for trees that could ameliorate the heat island effect, giving her the tools to effectively research which species would be most suitable.
Roads’ report for Clarksville includes an overview of heat island dynamics, an analysis of the city’s situation, and lists of recommended shade trees alongside limiting factors, such as invasive species to be avoided.
The ordinance observes that Clarksville’s tree canopy coverage is uneven, somewhere between 23 and 29 percent, depending on whether a few densely wooded parcels are included. This is roughly the same as Louisville, Lexington and St. Louis, but far less than the 40 percent goal set by these and other cities.
In crafting a policy for expansion of the canopy, Clarksville joins Louisville and New Albany in making an investment to hedge against rising temperatures. But it’s about more than global warming.
The ordinance provides a holistic picture of the beneficial role of trees in the socio-economic fabric of the city.
For example, it’s obvious that shade is a nice thing to have in the summertime, but it is not as commonly appreciated that it boosts property values (by a whopping nine percent). Or that it benefits business. Or that it can reduce the crime rate.
Using studies from other cities, the ordinance notes that shoppers spend 12 percent more in treed areas, and that a 10-percent increase in canopy cover results in an 11-percent decrease in crime.
For financially strapped city governments, trees are literally money in the bank.
“Using the base property tax rate in Town (.7232%) and the median home price, a nine percent across-the-board increase in home value would generate around $600,000 in increased annual revenue,” according to the ordinance.
Trees do incur costs for the municipality, but the ordinance supports the consensus emerging from cities such as Chicago, Portland and Seattle, and supported by the EPA.
“Although the benefits can vary considerably by community and tree species, they almost always outweigh the cost of planting and maintaining trees,” according to the EPA’s 2017 report, Reducing Urban Heat Islands.
That report found that for every dollar invested, trees returned three dollars in benefits.
In considering which trees to recommend, Roads took into account the context–public, commercial and residential. She also favored native species and noted the invasive species to avoid. She analyzed root systems, to determine how much room they needed to avoid interfering with sewer and septic systems, examining the particular soil needs of different trees, assessing their resistance to pests, determined the harmful or toxic effects of each plant to human and wildlife by investigating the leaves, fruits, thorns and bark.
Being able to applying skills developed in the sustainability and regeneration program to tackle a very specific and concrete real-world problem was uniquely gratifying to Roads.
“For me, it meant that I could make a difference small or big with the tools that I learned while taking classes at IU Southeast,” Roads said. “It means that I can use the information I learned in my field to educate others on the importance of sustainability and use it in real-life situations. It made me feel empowered that I can help the governments of cities decide on what are the best sustainable practices.”
For Taylor, the report demanded that Roads demonstrate mastery of a variety of academic and “soft” skills.
“First she had to be able to research the literature and then match to it to Clarksville,” Taylor said. “Second, she needed to advocate for native species, including explicitly which trees not to include because they are nonnative or even worse, because they are invasive. Thirdly, she need to make it valuable to the town.”
Taylor sees the tree project as emblematic of a degree program that leverages academic effort for the common good, and produces synergies that benefit both town and gown.
“The university should be more than just a place of student education and faculty research.” Taylor said. “The community should realize that we are a place of expertise and aid.”
Roads concurs, seeing immense social value in the relationship, which in turn bolsters her own enthusiasm for the field.
“This project validated my commitment [to sustainability] because while doing the research and analyzing data, it proved even more that everything is connected,” Roads said. “By recommending trees for Clarksville, Indiana, this project interrelated the people, the planet, and profits that these remarkable woody perennial plants provide for the world.”
Just as ecosystems are interrelated, so too are human societies. For good or ill, actions cannot avoid having an effect. Roads is profoundly aware of the correlation of human activity, such as population growth, and environmental degradation. She hopes her work can continue to contribute to improvements in all these areas.
“I want to be a part of the solution that can come up with innovative solutions so we can maintain a world where we can merge environmental, economic, and social interests in a positive direction.”
For Roads, planting Eastern redbuds and chinkapin oaks along busy commercial thoroughfares and augmenting residential neighborhoods with dogwoods and red maples is more than decoration. It’s a paradigm for survival.
“Sustainability is incorporated in our everyday lives, whether people know it or not,” Roads said.