Florida’s State Tree Has Mystery Ailment

YANKEETOWN, Fla. — The slender, majestic sabal palm depicted on Florida’s state seal bears little resemblance to the thousands of shriveling sabals dying along a stretch of Gulf Coast.

Scientists don’t know what’s killing the state tree, but a popular theory is that global warming may be to blame, causing a rise in ocean levels that choke the plant’s root system with salt water.

“This is the biggest die-off I’ve ever seen in Florida,” said Ed Barnard, who tracks dying trees for the state Division of Forestry. “It’s spectacular--in some areas it’s almost like a forest fire came through.”

Along 40 miles of coastal lowlands from Cedar Key to south of Homosassa Springs, the once vibrant green of healthy palm fronds has been replaced by the sagging yellow of the dying sabals and the bare, crumbling stalks of the dead.

“I just let the termites take care of them now,” said Dr. David Ohlwiler, whose 430 acres of untamed coastal forest here are studded by poles that were once palms. “It’s changed the whole landscape.”

When the Orlando plastic surgeon first called state forestry officials to take a look at his vacation property a year ago, he was surprised to learn they had heard nothing of the dying palms and that other residents appeared indifferent.

“It’s the state tree,” he said. “You would think more people would be concerned about it.”

The first and most obvious suspect was possible pollution from Florida Power Corp.’s sprawling generating and nuclear complex in nearby Crystal River, but Barnard and other state plant pathologists could find no pollutant, disease or insect killer.

“It appears to be the result of an ongoing ecological change,” Barnard said, noting that other sabal palm deaths have also been reported in small pockets at the mouth of Tampa Bay and near Jacksonville.

The case was turned over to a team of University of Florida scientists, who began examining the dying palms as a symptom of global warming and rising sea levels.

Years of burning fossil fuels have contributed to the so-called “greenhouse effect” in which built-up gases trap the sun’s heat, raise the Earth’s temperature and could cause a rise in sea level as the polar icecaps melt.

The rise along Florida’s north-central Gulf Coast has been particularly dramatic--3 inches over the last 70 years--according to a 1985 University of South Florida study.

The rest of Florida is protected by sandy beaches or barrier islands. But the low-lying coasts of Pasco, Hernando, Citrus and Levy counties are rimmed by salt marsh grasses with porous limestone outcroppings that support forests of pine and palm just inches above the salt water.

Kimberlyn Williams, an assistant professor of botany at the University of Florida, said salt water has apparently intruded into the coastal lowlands from rising sea levels and frequent flooding caused by storms and hurricanes.

“We noticed that the plants still growing around the dying palms are extremely salt tolerant,” Williams said. “The palms are also supposed to be tolerant to salt, but apparently they have their limit.”

Since surprisingly little is known about the palm, University of Florida scientists are testing the plant’s salt tolerance by conducting controlled greenhouse experiments and transplanting healthy sabal palms into badly affected areas. The research could take years, Williams said.

“It appears to be part of a whole community change, a conversion of coastal forests to salt marsh vegetation,” Williams said. “In the long run, the narrow preserves along the coast could slowly be eaten away.”