Tall Timbers was built on fire research. Scientists study fire’s impact on everything from plant community makeup and change to variability in dozens of animal species based on how frequently fire occurs on the landscape.
Some of this research has been ongoing since our organization was founded in 1958, and our pineywoods laboratory has helped develop innumerable best practices for using fire to support ecosystem health, biodiversity, and—importantly for humans—reduce wildfire risk.
In 1966, Tall Timbers embarked on a novel experiment using a 23-acre plot on the north side of Highway 12 in Leon County, Florida.
A photograph of NB66 taken the last year it was burned with prescribed fire.
At that time most people thought that frequent fire and the open pine woodlands they maintained was purely a human intervention, preventing natural succession to a closed canopy “climax” forest of beech, magnolia, holly, and spruce pine. Our researchers set up a grid of cement posts to see if taking fire out of some of Tall Timbers’ qual lands would result in this change, even if it took decades or centuries. A more modern view is that both fire-frequented pine woodlands and fire excluded hardwood forests had their well established places on the landscape, rather than one changing to another.
NB66, or No Burn since the winter of 1966, has been the subject of dozens of research papers and the source of a dynamic body of work studying what happens to the Red Hills ecosystem when fire is excluded from the landscape.
What resulted in NB66 is a common condition across the Southeast – a fire-excluded, overstory canopy forest with a loss of plant and animal diversity and accumulation of litter fuels. At the same time, certain species appeared, such as holly, spruce pine, hophornbeam, and beech, that supported the original prediction of succession towards a different, less fire tolerant kind of forest.
While it’s not an easy decision to end a long-term research project, changes to NB66 hold real-world value in researching the reintroduction of fire into such fire excluded areas.
In early 2025, staff guided timber crews as they thinned most of the hardwoods and left old remnant pines, establishing the next phase of research at NB66. This is a unique chance for Tall Timbers staff and property managers across the Southeast to learn about the process of restoring an area with 60 years of fire exclusion back to habitat for quail and hundreds of other species.
What did we learn at NB66?
Early researchers documented a slow decline in biodiversity in NB66 as the time since fire increased.
They observed two nearby reference ecosystems considered to be opposite ends of the succession process to help interpret some of the changes.
The first site was the Wade Tract, a nationally recognized, frequently burned, old-growth longleaf pine woodland where breeding bird populations had been counted repeatedly for several years. The second site was Woodyard Hammock, an important old-growth beech-magnolia forest on the western edge of Tall Timbers that represented the climax community as it was understood at the time.
As dominant plants in NB66 changed from herb to shrub/vine-sapling to canopy hardwood, wildlife responded.
The total bird species recorded on NB66 peaked during the first five years of fire exclusion and then began a steady decline as the time since fire increased. The total species count fell to a low point eight to 11 years following fire exclusion when hardwoods formed a low, dense subcanopy beneath the pines.
Stoddard Bird Lab staff documented changes in bird species composition every four to six years. The breeding birds found on NB66 changed rapidly when fire was initially removed. Within the first five years, several species disappeared from NB66 but remained common in the pinewoods surrounding the plot.
Within 15 years, fire-loving species such as the Red-Cockaded Woodpecker and Bachman’s Sparrows disappeared from the site. Northern Bobwhite occurred in the plot up to 1980 but became less predictable in the years that followed. Tree canopy species such as Eastern Wood-Pewee, Great Crested Flycatcher, Blue Jay, and Summer Tanager seemed least affected by vegetation changes and came to the site over time because of fire exclusion.
Changes in the mammal community were equally as dramatic as those seen in the avian community. Species typical of open pinewoods, such as the cotton rat, disappeared, and species more associated with mesic or wetter conditions, such as the white-tailed deer, wood rat, opossum and raccoon, appeared within 15 years of fire exclusion.
What’s next?
With NB66 now becoming an experiment on how to restore areas where fire has been excluded, the next steps include establishing research plots to examine the effectiveness of forest, buffer, and erosion gully restoration.
The Tall Timbers Land Management team will soon introduce regular prescribed fire, herbicide and other treatments into the research plots, except for one area that has been retained as an unburned plot to compliment unburned Stoddard Plots.
New research at the NB66 site has important applications in the real world, where land managers—whether new or experienced—often face questions about how to reclaim fire-excluded stands.
Research Director Morgan Varner said this work at NB66 provides a unique chance to conduct additional relevant research and, due to its size and ecosystem variations, NB66 can help answer more applied questions as they arise.
“It is an experiment, but it will also incorporate an element of adaptive management,” Varner said. “If we see a problem that managers are having or a question that is relevant, we’ll address it.”
NB66 was the last area Red-Cockaded Woodpeckers were found on Tall Timbers before they left the property and were then reintroduced in 2006.
“A success for me is to see a covey of quail flushed or a Red-Cockaded Woodpecker return to the area,” Varner said. “From a restoration standpoint, it’s going to be an interesting site.”
