Termites leave older trees gutted, vulnerable

Experts alarmed as invasive species finds new sources of food

A species of invasive super termites is taking their voracious appetite from dead wood and timber to South Florida’s live trees, hollowing out decades-old canopies and making them vulnerable to high winds.

The change in strategy by the newly arrived Formosan and Asian subterranean termites is alarming to experts who say they are seeing signs that normally wind-resistant trees such as oaks are being compromised and put at greater risk of being toppled during tropical storms and hurricanes.

“I would say in the last seven or eight years we’ve begun to see termites that attack trees with more frequency than maybe we have seen prior to that time,” said Michael Orfanedes, commercial horticulture agent with at the University of Florida’s Institute of Food and Agricultural Sciences in Broward County.

Normally termites make their homes in dead or harvested wood, such as timber used in houses and other construction.

But the more voracious species, often called super termites, are finding new sources of food in some of South Florida’s largest and oldest living trees from Palm Beach County to the Keys.

“That’s one of the big things I’m concerned about, especially in

South Florida, and especially here in Broward, where we have a big population of Asian subterranean termites that within 20 years have spread extensively from the old part of the city like New River, Riverside (Park), Riverland, all of these areas with beautiful old canopies,” said Dr. Tom Chouvenc, urban entomology professor at UF/IFAS.

March is the beginning of termite swarming season, when hundreds of thousands of termites take to the air in search of mates to establish new colonies.

The termites are most attracted to trees that have wounds from chainsaws, lightning, stress or other damage, said Jimi LeGette, certified arborist and president of Lauderdale Tree Service. Healthy trees emit a pheromone that repels insects such as termites, LeGette said, but damaged trees do just the opposite, attracting the hungry termites that set up massive colonies in tree trunks.

Orfanedes said older trees are particularly vulnerable to the new breed of invasive termite in South Florida.

“The difference now is some of the species that we see that are new to the area are capable of actually hitting on living tissues in trees, so that’s the change,” he said. “So, we are concerned about it, and this particular new termite, the Asian subterranean, is, I guess, perhaps of the most concern.”

Experts recommend inspecting trees annually — preferably by a certified arborist — to detect these troublesome termites early. They said to look for mud tubes, which are like tunnels the termites use to travel.

Although experts such as Orfanedes said action is needed, the situation is not yet dire enough to start cutting down trees.

But, Chouvenc warns, “as the invasive species keeps spreading, more people will be impacted in the future. At least if people understand the threat is here, they can do the right thing.” He is trying to initiate a pilot study in Fort Lauderdale to annually inspect trees in public areas. That way, he said, it could allow the city to track the termites’ local impact and detect infestations.

Orfanedes said about 95% of the trees that were toppled by Hurricane Irma in 2017 were due to improper pruning or root issues. The next time around, he said, termites could contribute to the loss.

“I think Irma was kind of a dress rehearsal for this. I’m really concerned that we will lose a lot of these trees that were very old, very big trees, that may have been gutted out by this invasive termite,” Chouvenc said. “I would argue that we’re kind of in the process of irreversibly losing part of this historical canopy because when we get hit by a hurricane we’re going to lose a lot of these trees, more than we should have if not for the termites.”