MIAMI — About half of Miami’s signature native trees — including the live oaks that line the streets of Coral Way and towering sabal palms that are the state’s official tree — might not be able to handle the rising temperatures caused by climate change.
Researchers from the University of Miami looked at hundreds of South Florida’s diverse plant species and tried to answer how, or if, the trees will survive the heat expected in the coming decades.
Kenneth Feeley, a UM biology professor and director of the university’s Gifford Arboretum, believes the findings will shape the look of the South Florida landscape over the next century — and perhaps should be guiding some tree planting decisions being made today.
“Unfortunately many trees will be lost and that’s a consequence of modern climate change,” Feeley said. “Should we continue planting with some of these same native species or do we need to diversify our urban forest to incorporate more species for hotter places?”
In the next 50 or 60 years, he imagines the trees we see at our parks, or on the way to the grocery store might shift toward more exotic species that flourish in the greater Caribbean. That also might create more habitat for exotic animals as well, like the populations of tropical parrots that already thrive in South Florida.
Some natives are clearly more vulnerable than others. Take the live oak. Miami and the Florida Keys already one of the hottest place in the world that it grows. Feeley expects the oaks, and many other natives trees, like the bald cypress, slash pine and red maple, will show signs of stress as the average temperatures continue to rise and be at greater risk of die off.
Feeley and his doctoral graduate student, Alyssa Kullberg, were able to estimate up to 41 percent of Miami’s native trees will experience heat stress by looking at global data bases of where the trees occur around the planet and cross referencing that with the Miami’s current and predicted maximum temperatures.
For many South Florida natives, the mid-80s is the best temperature for photosynthesis, the process where plants use light, carbon and water to grow and make oxygen. With extreme temperatures, Feeley said plants and trees will struggle and, for humans, provide less shade and cooling.
“They’ll be taking up less carbon. Their leaves might not be as lush so they won’t provide as much canopy cover and as they get hotter, they also become more susceptible to disease and pests,” he said.
UM’s work on trees isn’t just academic curiosity. Jane Gilbert, Miami-Dade County’s chief heat officer, told the Herald that the county met with the researchers and will factor the findings into decisions on what to plant along streets, in public places and what to recommend that residents plant.
That’s not as simple at it may sound. There are lots of considerations city planners think about. Can trees withstand hurricane-force winds? Are they invasive species, likely to spread and crowd out natives? Feeley also
Mer. Gen 8th, 2025
