Environment

Atlanta’s Tree Canopy May Not Have Shrunk, But It’s At Risk

The city of Atlanta is working on revising its tree ordinance, but with the city’s real estate market booming, more trees are coming down.
The city of Atlanta is working on revising its tree ordinance, but with the city’s real estate market booming, more trees are coming down.
Credit Al Such / WABE

Atlanta’s famous tree canopy is degrading, according to a study conducted for the city of Atlanta. The research, by Georgia Tech professor Tony Giarrusso, shows that while Atlanta’s tree canopy hasn’t shrunk, the quality of trees has gone down.

In 2008, Giarrusso, the assistant director of the Center for Spatial Planning Analytics and Visualization at Georgia Tech, used satellite imagery to survey Atlanta’s tree cover. In 2014, he did it again, to see what changed. His final report isn’t yet out, but on Thursday he presented his findings publicly for the first time.

He said just looking at the overall percentage of tree canopy cover in Atlanta, there wasn’t much change between 2008 and 2014, “but as we got on the ground and started to look at things, we noticed a lot of the things that we saw as gain were not true gain,” he said.

That’s because the gains in trees were mostly in what he called “pipe farms” — places that were cleared for development before the recession, never got developed, then fast-growing pine trees sprouted up.

Those temporary forests don’t really make up for the old hardwood forests that had been in those places before, said Giarrusso.

The losses in trees between 2008 and 2014 were mostly on private property. Many of them, said Giarusso, were on lots where smaller homes were replaced with big ones.

“The phenomenon of redeveloping single-family homes to build out to the maximum allowable lot coverage. That was really by far the eye-opener,” he said. “Lot-by-lot loss. And it’s sneaking up on people.”

The city of Atlanta has a goal of 50 percent canopy cover. According to Giarrusso’s study, as of 2014, it was at about 47 percent.

“Planting is not going to keep our city anywhere close to 50 percent,” said Greg Levine, co-executive director of Trees Atlanta. He said he’d like to see more trees saved on individual lots, denser development and investment by the city in protecting bigger areas of forest.

Trees Atlanta hosted Giarrusso’s presentation Thursday night. He said he will release the report in the next few weeks, and he plans to begin another update on Atlanta’s tree canopy this year. Giarrusso said he expects that will show more change than the 2014 update does.

“The economy is related to the canopy. As the economy gets better, the canopy takes a hit,” Giarrusso said.

The city is working on revising its tree ordinance, but with the real estate market booming in Atlanta, more trees are coming down.

“Clearly, as you go around the city, we’re losing lots and lots of acreage,” said Levine. “I think the 2018 data is going to scare people.”