Sandy Springs lost more than 80 acres of tree canopy due to the Transform 285/400 improvement project, according to the city’s 2023 Tree Canopy Study Update.
Bridget Lawlor, the city’s geographic information system (GIS) manager, said Sandy Springs’ canopy covered 55 percent of its 38.5 square miles in 2023, a half percent lower than in 2021.
Brookhaven measured the tree canopy of its 12 square miles at 48 percent in 2021, according to the tree canopy study. Chamblee measured its canopy at 36 percent of its 7.7 square miles in 2017. Atlanta reported 47 percent of its 136 square miles was under tree canopy in 2018.
Sandy Springs Urban Forester Willie Park said during this week’s city council meeting that lack of funding prevents other cities’ GIS departments from doing canopy studies more often. Their original studies were probably done when those cities sought Tree City USA or Tree City of America credentials and they haven’t repeated the studies.
Park cautioned the city council and Mayor Rusty Paul that canopy coverage is not the only indicator of a strong, resilient urban forest. The city needs to infill existing forest areas to increase its health and resilience, he said.
“I would like to use this data to do very targeted plantings to maximize the effects of our tree fund dollars, and really push that needle forward,” Park said.
Lawlor said the AI model does a better job of picking up the tree canopy along the edges of tree cover in areas next to parking lots. She said the lack of tree canopy within stream buffers seems to result from either open water or low vegetation.
“It’s not always necessarily development or impervious surfaces,” Lawlor said.
Lawlor said the city conducts a tree canopy study every other year. The latest study used artificial intelligence (AI) data from 2017 and 2023. She said the AI data is more accurate than the pixel classification method, which is more labor-intensive. In 2017, 2021, and 2023 the AI data had better than 95 percent accuracy. The pixel method was never better than the 92.4 percent accuracy attained in 2019.
