New ordinance aims to restore Chattanooga’s shrinking tree canopy 

Chattanooga’s tree canopy has steadily eroded over the past few decades, with negative impacts to both environmental health and residents’ quality of life.

New regulations approved by Chattanooga City Council on April 8 aim to regrow some of the city’s lost tree cover.

According to a paper published last year by researchers at the University of Tennessee at Chattanooga, the forested areas of Chattanooga declined by 43% from 1984 to 2021. Over the intervals studied, the biggest decrease in forest vegetation occurred between 2019 and 2021. 

“We have to look at this holistically for the city overall, and we need more tree canopy, and we’re losing it,” said Chris Anderson, advisor to Mayor Tim Kelly. “So we have to reverse that and increase instead.”

Public tree protections

A new provision in the tree ordinance calls for the inch-for-inch replacement of city-owned trees. For instance, if homeowners cut down a street tree with a three-inch diameter trunk to expand their driveway, they’d have to replace it with three inches of new tree trunks. Or, they can pay the city a replacement fee at $200 per inch. 

The new rules protect roots, too. Damage to a certain percentage of a tree’s root system triggers the need for replacement. These rules protecting public trees and their roots apply to homeowners and large-scale developers alike.

 ”A lot of developers that I consult with intend to keep the trees, but they don’t know enough about trees to be able to do that,” said local arborist and Chattanooga Tree Commission member Benjamin Moore. “So this ordinance does speak to that and gives people guidelines.”

Private tree protections

Outside the form-based code area, developments larger than an acre have to meet new tree-retention requirements. A two-acre housing development in Brainerd, for example, must have 72 inches of tree trunk on the property when construction ends, either by retaining existing trees or planting new ones.

We know that increasing the canopy is very, very difficult, and trees do everything in tree time. You can’t replace that hundred-year-old tree lickety-split.

— Benjamin Moore, Chattanooga Tree Commission

Developers can avoid the requirement, though, with a payment to the city offsetting the missing tree cover.

“ You’ve probably got a handful of builders that are doing about that much already per acre. Some are not, but they all should be,” Anderson said. “ It’s not onerous, it will not significantly increase the cost of housing.”

For existing properties, there are no new regulations on privately owned trees — homeowners can do what they want with trees in their front and back yards.

The ‘tree bank’

Fees for permits to remove city trees and replacement and offset payments will land in a new fund called the tree bank. City Forester Pete Stewart will control the fund to plant new public trees across the city.

“ There’s a lot of developments that can’t preserve their trees, and so that tree bank provides that vessel,” Moore said. “It is a deterrent as well.”

Still, Moore said the goal of the ordinance isn’t to diminish development or clog up the permitting process. Instead, it’s designed to protect the public goods provided by Chattanooga’s urban canopy — shade, air quality, stormwater mitigation, and more.

Not a quick fix

Tree replacement, both on public and private property, doesn’t fully recover the value lost by felling mature trees, Moore said.

The older and larger the tree, the greater the benefits to residents and the surrounding ecosystem. By requiring lots of new, young trees following construction, restoring Chattanooga’s urban forests will be a decades-long project. 

“We know that increasing the canopy is very, very difficult,” Moore said. “And trees do everything in tree time — you can’t replace that hundred-year-old tree lickety-split.”

Overall, Moore called the updated ordinance a good first step in tree protection. But he said the inability to regulate trees on residential properties is a weakness in halting the loss of city greenery.

“That’s infringing on people’s personal property rights, so  how far do we want to go is kind of the question,” he said. “ I don’t have a great answer for that.”

---

Contact William at william@chattamatters.com