UF scientists are working to save North America’s most endangered tree: the Florida torreya, located in the Panhandle.
The leaves fluttered as the humid North Florida wind blew off of the sandy banks of the Apalachicola River through the thick woods of Torreya State Park in Quincy, Florida. As the sun beat down on a canopy of trees, Jason Smith—a University of Florida associate professor of forest pathology—knelt, his hands cradling a seedling of the Torreya taxifolia, the most endangered tree in North America.
The torreya tree—also known as the Florida nutmeg or stinking yew, for the resulting rotting smell yielded by the production of its seed— was once abundant in the north Florida woods, its nearly 60-feet stature providing a home for small animals and insects.
Today, the tallest recorded torreya in the state park is 10 feet tall. With a recorded 746 trees left in the wild, the Florida torreya is approaching extinction. Smith has been involved in research efforts to combat the torreya’s extinction since 2007. But it was not until a camping trip in March 2017 to Torreya State Park, the Florida torreya’s only habitat, that he understood the full scope of the problem.
“I just couldn’t believe how much worse they looked,” Smith said. “That’s really what prompted me to think that we really need to do something much bigger.”
In a last resort effort to save the tree, Smith organized the Torreya Tree of Life conference, which was held on March 1 and 2 at Torreya State Park to bring scientists together to develop a plan to save the tree.
“It’s on a trajectory towards extinction,” Smith said. “At the same time, there is a path forward. There is a way for us to stop this.” In the early 20th century, the torreya was a healthy component of the forest along the Apalachicola, it’s needle-like leaves creating a dense canopy. There were over an estimated 500,000 in the wild, and the Apalachee and Creek used it for timber; colonists and settlers would use them as Christmas trees.
In 1936, researchers began to notice a stark decline due to fungal pathogen thought to come from China. Not much is known about the pathogen except that the torreya is extremely susceptible to it. Researchers have yet to conclusively identify the disease or its source, and some speculate it may even be an amalgamation of diseases. But researchers do know how the pathogen kills the tree: It kills the stems of the trees, forcing them to resprout from their base. Most of the remaining individuals of the species are sunken and
feeble, bearing little resemblance to the characteristically full-bodied, towering tree.
“Not only do we have very few [left], they don’t really represent what the species should look like,” Smith said. “It has always been a rare tree, but it had a healthy, viable population prior to 1936.”
At the conference, Smith—and the researchers he brought together—presented their current research on the torreya, planted torreya saplings, hiked through the state park to observe the effect of the fungal disease. One of the goals was to document the biodiversity associated with the Florida torreya—that is, to create a “torreya tree of life.”
“The tree is such a unique component of the region’s biodiversity that there are dozens, if not hundreds of species dependent on it.”
“We’ve always struggled to get anybody concerned to do anything,” Smith said. “So I thought, ‘we got to do something different, we got to work outside the box.’”
Pamela Soltis, director of UF’s Biodiversity Institute, spoke at the conference about the tree’s evolutionary history and what is known about its larger role in the Apalachicola ecosystem. Some biologists believe the tree is an evolutionary anachronism, meaning that its evolution and place in North Florida is likely only explained through coevolution with another species that has since gone extinct. It’s thought to have been brought down from Appalachia by a large tortoise. The torreya prefers to grow on north-facing steepheads, a kind of sheer-walled ravine that’s more akin to northern terrain than flat Florida.
Soltis—who is also a botanist and the curator of molecular systematics and evolutionary genetics at the Florida Museum of Natural History—is working to construct the first family tree of the species, as well as the first preliminary genome sequence. Mapping out the closest relatives of the North Florida torreya may make it possible to hybridize, and understanding its genetics will be helpful for targeting fungal-resistant genes, Soltis said.
“Because they declined so rapidly, we don’t know what all those connections might be,” Soltis said. “We’re left to speculate what some of the problems might be if it does go extinct.”
The tree is such a unique component of the region’s biodiversity that there are dozens, if not hundreds of species dependent on it. Its extinction could threaten the other species that make it their home.
“This is not a singular issue,” said Olivia Johnson, a first-year forestry student. “It’s happening to many other animals and trees around the world. With this tree, since its going extinct, it’s just like a loss of history.”
Rescuing the torreya, at least in the tree’s current state may not be possible, but the Torreya Tree of Life conference was the first step in what Smith in the effort.
“There’s countless discoveries to be found with these plants,” Smith said. “It represents untapped resources and untapped value. You take that away and it changes everything.”•