ATLANTA—If the streets seem a little brighter in Atlanta neighborhoods, you’re not imagining things. The so-called “City in the Forest” is gradually losing its mature tree canopy. An Urban Tree Canopy study by the City of Atlanta revealed that .43 acres of canopy was lost per day in the decade leading up to 2018, mostly due to development. And it’s not just Atlanta: the Nature Conservancy cites a study that estimates that urban tree canopy nationwide is declining more than 1 percent annually.
While development shows no signs of slowing, Atlanta’s trees have a newer threat: increasing severe weather caused by climate change.
The loss of trees from storms is increasing “two- or threefold,” says Christie Bryant, an Atlanta-based certified arborist and an ISA Tree Risk Assessment expert. “The weather is becoming more extreme, and our winds are becoming more extreme.”
“Urban trees in particular grow in a very different environment,” notes Camilo Ordóñez Barona, a post doctoral fellow in the Geography, Geomatics and Environment department at University of Toronto at Missisagua. “They grow where soil tends to be shallow, and they’re surrounded by impervious surfaces so they can suffer from drought. Climate change [will definitely] affect urban trees, particularly mature trees.”
Ordóñez Barona says the increase in heat waves, storms, droughts, and floods can inhibit photosynthesis, damage roots and branches, decrease stability, and increase pest infestation and decay, among other factors.
Spooked homeowners also are increasingly removing trees to prevent them from falling during the next storm and causing damage or injuries. In Atlanta and other municipalities, a permit is required to remove a tree, and in most cases, according to the city’s Tree Protection Ordinance, the tree must be dead, dying, diseased or hazardous.
“But people’s fear reactions are causing more trees to come down because of small defects,” says Bryant. “Our ability to assume risk is going to have to increase if we want to be the City in the Forest.”
When a mature tree is removed, whether it’s cleared for development or because it is deemed a potential risk, Bryant says it puts neighboring trees at risk, because the remaining trees are now exposed to wind dynamics.
“It is just compounding the problem,” she says.
Losing large trees in a community has other repercussions. According to the Nature Conservancy, trees make cities cooler in the summer (leading to as much as a 7 percent reduction in energy usage from air conditioning) and improve air quality.
“There are also social benefits of having big trees around,” says Ordóñez Baron. “They are symbols of nature and make people and communities feel good.”
Bryant says the best thing a homeowner can do to contribute to the loss of mature trees is to keep trees on their property as healthy as possible.
“Establish a relationship with an arborist so you’ll be protected from unscrupulous tree companies,” she says. “Have your trees checked out.” Many potential issues can be averted, such as treating for pests and diseases, trimming dead or dying branches, or removing vines weighing down boughs
Ordóñez Baron adds that identifying trunk decay, amending soil with nutrients, and watering trees during a drought will also help keep mature trees healthy.
And it’s important to remember that trees may be stronger than we give them credit.
“Trees are very resilient,” says Ordóñez Baron. “A lot of trees can survive damage, windstorms, and severe storms. If we let nature do its thing, nature will do its thing.”