If you’ve ever walked down Gay Street in the middle of a summer day, you might have wished for more shade. Lots of concrete, or impervious surfaces, makes it hard to plant trees there. But Knoxville has been tracking its tree canopy for the last 10 years, and urban tree planners are expanding tree coverage with the help of community stakeholders and city departments.
A tree canopy is the umbrella of shade that is given by mature branches and leaves at the upper-most level of the tree. As of a 2021 assessment, Knoxville’s tree canopy covers about 24,000 acres, or 38% of the city’s land area. The goal is to increase that coverage to 40% by 2040, with the help of two grants, one for $1.7 million to the city, and another for $2.3 million to the University of Tennessee.
Part of that money will help educate the community about the benefits of a robust tree canopy. Industrial and commercial areas have done well in terms of preserving tree canopy over the last decade, according to the 2021 assessment. But homeowners and subdivisions have been less successful.
“Almost 75% of all of our tree loss that we saw was occurring mainly on residential property,” said Kasey Krause, an urban tree forester for the city of Knoxville and one of the leaders of the Urban Tree Master Plan.
Residents often don’t know how to care for trees, or simply find it too expensive. Krause said homeowners often just get rid of the tree.
“And that kind of reverses what our strategy is,” he said. “In Island Home neighborhood, where it's one of the heaviest percentages of tree cover that we have across the city of Knoxville, we saw one of the sharpest decreases in the amount of tree cover in that specific neighborhood.”
Similarly, neighborhoods like Holston Hills, Sequoyah Hills and Fountain City East saw some of the largest amount of tree loss over the 10-year span, at about 6% of their totals. In those areas, Krause said, planners will look at preservation strategies to try to reverse that trend.
Household income correlates to urban tree coverage
The grants from the Department of Agriculture Forest Service will fund a multiyear tree canopy project, and a collaboration with the Knox County school system for education and internships, as well as SEEED Knoxville (Socially Equal Energy Efficient Development). The University’s project is granted by the USDA Tree Service to build tree canopy and storm water runoff infrastructure around the university’s campus. These projects are being operated separately but aim for similar results.
This allocation of funds is an effect of the White House’s Justice40 initiative, which recommends that 40% of all federal aid should be used towards underprivileged communities. Research suggests that as household income rises, so does the amount of urban tree coverage, leaving lower-income communities with fewer of the benefits of shade, walkability and social connectivity. Shade, for example, can help reduce temperatures by up to 3 degrees, according to the EPA.
In Knoxville, areas such as Fourth & Gill, Parkridge and Marble City have the lowest amounts of tree coverage after the university campus and downtown, and less privileged communities will be the beneficiaries of the city’s tree coverage budget.
Other benefits of an established canopy include increased property value and lower crime rates, but also environmental benefits like flood prevention.
The university grant will be used in part to build gravel tree pits to help prevent flooding from storm water runoff.
“These systems have the potential to be much cheaper than a lot of other storm water practices that we use,” said Jon Hathaway, an engineering professor at UT. “And so I'm hoping that we can get more benefits for a lower price, which could be really appealing to a lot of communities.”
Tree canopy also makes an area more desirable for businesses. An area with trees “is a place where businesses are going to want to locate and people are going to want to shop there,” Krause said. “We know that that attracts business and vendors to those shopping centers.”
City planners are seeking public input and involvement. A first tree planting event will take place Dec. 16 at Caswell Park, to plant 20 trees, and more events will follow through March.
(This story was co-produced with students from the University of Tennessee's Department of Journalism and Media.)