Burning for the Birds at Piedmont NWR
It began with a hot fire – trees scorched to the top, a mile long stretch of highly visible forest turned brown. It ended with a five-fold increase in an endangered species. What was it? The answer is a prescribed fire.
Piedmont National Wildlife Refuge is in middle Georgia, about 20 miles north of Macon. More than two-thirds of the refuge is covered in loblolly and shortleaf pine, with the rest evenly distributed between upland and bottomland hardwoods. In these pine forests lives a unique, endangered bird – the red-cockaded woodpecker (RCW). The species is unique because it’s the only North American woodpecker to peck cavities in living trees. A breeding pair excavates a cluster of cavity trees at one site. Red-cockaded woodpeckers are endangered because they are specialists. Their nesting habitat is large diameter, old pine trees with little to no woody mid-story vegetation. The large old pine trees are mostly gone because they’re compatible with neither pine plantations nor subdivisions. The woody mid-story is thick due to fire suppression. This is where prescribed fire comes in.
Prescribed burning is fire, applied under exacting weather conditions, designed to achieve specific objectives. That’s what the refuge does to reduce wildfire potential and provide habitat for the RCW. There is a reason it’s not called controlled burning: fire managers don’t control all the variables influencing fire. They cannot because there are too many. These unaccountable variables lined up such that one of the refuge’s prescribed fires “over-achieved.” Usually “over-achieved” prescribed fires generate negative outcomes.
On March 25, 2003, the refuge conducted a prescribed burn in compartment 15. A combination of events – lower humidity, shifting winds along a road frontage, and the firing pattern – led to unexpectedly high fire intensity and excessive crown scorch.
The expectation was that a high percentage of the trees would die; however, they didn’t. Southern pines are highly resistant to fire-caused mortality. Though, much of the mid-story did die. Since a primary objective was to continue reducing mid-story, the unit was burned again in February 2005.
The historic fire return interval in the south was short (less than five years), and mid-story was still excessive, so once again the unit was burned, this time in February 2007.
At this time the mid-story was greatly reduced. Since the unit had been burned three times in a five year time span it was decided to give it a rest and go four years without burning. That was a mistake.
Obviously the mid-story wasn’t killed as anticipated. The prescribed fire only top-killed the mid-story, burning the foliage and some of the small branches. It was all still there, waiting for a sufficient fire-free interval to grow back. The growth interval doesn’t need to be long, either. From the time of the September 5, 2007 photos until the unit was burned again in March, 2011, the mid-story grew to the height of an average person.
How did the RCW respond to this burning? Breeding season monitoring for the past eleven years is as follows:
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The long-term goal for in compartment 15 is 674 acres of RCW habitat. With five clusters this is 135 acres per cluster, just over the 120-acre minimum. The compartment is now in a maintenance mode.
What are the lessons learned from the past decade of fire management in compartment 15? Frequent prescribed fire is necessary to reduce the risk of wildfire and assist recovery of the endangered red-cockaded woodpecker on the refuge. Waiting more than four years between prescribed fires or a wildfire is too long. The average burn rotation should be two to three years. Continue that regime, and the refuge will be well on its way to meeting its risk reduction and recovering its RCW population goals.