Fire suppression is threatening the endangered pine rockland forest of No Name Key, which will eventually become a hardwood hammock if new management practices aren't adapted, a peer-reviewed study released in October found.
However, an attempt by the National Key Deer Refuge to reintroduce prescribed burns on No Name "will be a daunting task for land managers," due to the amount of understory vegetation and tinder that has built up since the refuge took control of most of the island in 1957, wrote the authors.
The study, which appeared in the "International Journal of Wildland Fire," was conducted by geologists Grant Harley, Henri Grissin-Mayer and Sally Horn of the University of Tennessee in Knoxville.
The pine rockland ecosystem, which is dominated by the tall but skinny slash pine, is unique to South Florida and the Bahamas. Such forests once covered 185,000 acres in South Florida. But agricultural and residential development have reduced the range by 90 percent over the past century. Today, South Florida's pinelands are found only in the Big Cypress National Preserve, Everglades National Park and in the Lower Keys.
Using new dating techniques for the slash pine, the authors compared the fire histories since the 1700s of a healthy section of pine forest on Big Pine Key called Boneyard Ridge with an unhealthy section of pine forest in central No Name Key. Healthy slash pine forests are characterized by a low density of other vegetation, including shrubs, forest brush, palm trees and other understory trees.
Both tracts analyzed in the study are slightly more than a quarter square mile in size and are within the 9,200-acre National Key Deer Refuge. They make up approximately 20 percent of the slash pine forest in the Key Deer Refuge.
The authors found that fires of varying intensities at the Boneyard Ridge site had broken out an average of every three to six years over the period of study. On No Name Key, fires typically took place every nine to 11 years. That information, combined with earlier observations of the No Name Key tract, led the authors to conclude that the area likely always had more underbrush than the Boneyard Ridge tract on Big Pine.
Nevertheless, fire suppression has likely worsened conditions there since the advent of the refuge in 1957. In the past 55 years, the No Name site has had just one natural burn -- a small 2003 wildfire that was quickly suppressed. Its only prescribed burn to reduce natural fuel loads was in 1992.
In contrast, there have been five prescribed burns since 1957 in the much healthier Boneyard, including three since 2000.
As a result of the lack of fires, other foliage has begun to squeeze out the slash pines on No Name Key. The pine stands "are likely to succeed to hardwood hammock, if fire is not reintroduced," the authors wrote.
In an interview last week, author Harley said he believes refuge managers must do a No Name Key burn in the next five to six years if they wish to save the island's pine rockland ecosystem. Burns throughout No Name's slash pine community need to be conducted approximately every 10 years to maintain its health, he added.
Dana Cohen, fire management specialist for the Key Deer Refuge, said she is well aware of the threat.
"We should be very concerned about losing the pine rockland forest on No Name Key," she said last Friday. "These last parcels we have are critical for biodiversity."
But she said refuge managers are hampered by several constraints when it comes to conducting prescribed burns.
Chief among them is funding. As recently as early last decade, the refuge had the budget to burn several hundred acres in a year. By 2011, that figure had been reduced to 30 acres, Cohen said.
That means prioritization becomes more paramount, and because the forest on Big Pine is more pristine, it is first on the list for prescribed burns.
Refuge managers also have to worry about assuaging public concerns as they move forward with burns. That's always the case among residents in proximity to a burn site. A burn on Big Pine in 2011 that got out of control and led to precautionary evacuation of nearby homes has heightened sensitivity about this issue, Cohen said.
Still, she said the goal of National Key Deer Refuge managers is to do a prescribed burn on some portion of No Name Key within three to five years. She added that there are some areas of No Name Key that she believes could safely be burned without first removing dead vegetation from the forest floor.
But like the study's authors, she acknowledged that a mechanized cleanup would be a necessary precondition to do a prescribed burn in much of the No Name portion of the refuge.
"It's a very difficult conservation situation," Cohen said.