Development in Gainesville threatens the future of its live oak population.
About 20 minutes north of Gainesville in an open field in Alachua stands the Cellon Oak, the largest live oak in Florida. The tree, nicknamed Atticus, with a massive 85-foot trunk and a canopy that sprawls 160 feet across the sky, is estimated to be anywhere between 300 and 500 years old.
Quercus virginiana, commonly known as live oaks, are Gainesville icons. The evergreen tree’s large, Spanish-moss-adorned branches swoop down to the ground in a phenomenon known as “decumbent branching.”
Live oaks were once scattered across the city. But as the savanna, the tree’s natural habitat, is increasingly transformed into paved parking lots or plots destined to become apartments, the typically resilient trees have come under threat, said UF botanist Francis Putz.
In 2003, Putz conducted a study that found that 90 percent of live oaks in Gainesville’s suburban areas weren’t getting enough sunlight due to overcrowding by taller trees, namely the sweet gum, magnolia and, laurel oak that don’t need as much space to establish a root structure. Three years later, Putz and graduate student Tova Spector found that a similar phenomenon was occurring in the county’s rural areas. The establishment of pine plantations had decreased the open savanna cover from 70 percent to less than 30.
Putz’s research led him to conclude that encroaching trees were in danger of destroying more than half of Gainesville’s live oaks in a process that could take anywhere from 10 to 30 years. 12 years later, Putz believes nearly 97 percent of the county’s savanna has been lost, taking many live oaks with it.
“[Live oaks have] to be the right tree in the right place, and you have to make room for them,” Putz said. “But a lot of developers are unwilling to make room for them.”
One big tree is worth how many small trees? You take down one big tree and you plant ten, twenty or one hundred small trees, but they hardly make up for it.
Live oaks can live to be centuries old, so while the population isn’t in imminent danger, the practices that hurt trees now could cause their disappearance in the future. Putz found that a combination of heavy rainfall, an increased use of lawn fertilizers, a decrease in fire suppression and, of course, a warming climate, give tall, fast-growing tree species an ecological edge.
For example, laurel oaks compete with (and tend to beat out) nearby live oaks for the resources necessary for healthy development, like water, soil nutrients and sunlight. Where live oaks grow horizontally, laurel oaks grow vertically,
forming a dense canopy above the former tree that blocks sunlight. Laurel oaks also tend to live less than a century and aren’t as hurricane resistant as the sturdy live oaks.
Gainesville offers several resources in order give heritage trees a fighting chance. In 2013, the city commission approved a tree ordinance to protect 25 heritage tree species, including live oaks and longleaf pines, whose population has also rapidly declined in the industrial age.
Developers desiring to take down regulated trees on commercial property are required to pay a mitigation fee. This fee is put toward a tree fund that the city uses to plant new trees in the community. Homeowners who take down a protected tree located on their property have to plant trees to make up for it.
“If a tree needs to be removed, the tree is mitigated for,” said Matthew Mears, the city arborist. “It’s not just gone forever.”
Putz said that though these efforts are great, the city and developers often plant live oaks “in places where they can’t do live oak things,” like extend their roots 100 feet into the ground and grow big, branching canopies.
“One big tree is worth how many small trees?” Putz said. “You take down one big tree and you plant ten, twenty or one hundred small trees, but they hardly make up for it.”
The city commission has also developed an Urban Forestry Management Plan, a community-driven effort to improve the local forestry and landscape. The plan hopes to identify challenges to the ecosystem, such as hurricanes and laurel oak encroachment, combat them and find ways to diversify the city’s urban forestry.
In addition to the ordinance and its conservation projects, the city also holds monthly public meetings on the issues faced by trees in Gainesville. Mears and Putz both said the best thing individual citizens can do is let the city know you care about trees. •