Hurricanes serve as a unique player in the long-term health of forests and the behavior of fire for years after cyclones pass through.
They shake loose decaying limbs, helping to thin out the overstory, but can also level trees which, in turn, become a tinderbox that increases the risk for more severe wildfires in the future.
The growing intensity of hurricanes also has an impact on the work being done in the Red Hills to reestablish the endangered Red-cockaded Woodpecker.
Five years since Category 5 Hurricane Michael carved a path from its landfall at Mexico Beach up through rural Florida and South Georgia with hurricane-force winds, the evidence is still apparent.
Pines, oaks and other trees are still crisscrossed in tangles in some places along Michael’s route through the western edge of the Red Hills.
It’s here on the North American Coastal Plain where Tall Timbers Post-Doctoral Research Scientist Nicole Zampieri did part of her Ph.D. research surveying longleaf pine habitats before and after Michael to determine how such a massive storm would impact the forest.
It was by happenstance, though.
Zampieri was already studying stand structure and growth rates in the remaining longleaf pine ecosystem, where she collected data from 20 sites around the region. Then Michael came through, providing a once-in-a-lifetime chance to document such stark changes.
What she found was high tree mortality – 88% where the eye of the storm passed and 98% among medium sized trees between 13 and 15 inches in diameter – which poses a threat to natural forest regeneration within the longleaf system. Just 3% of the longleaf pine ecosystem remains after it was
heavily harvested from the 1880s to the 1920s. At one point, it covered 92 million acres from Virginia to Texas. Today only about 5 million acres remain.
Zampieri’s summation was that with long-term shifts in climate and the increase in intensity and frequency of major hurricanes, and the damage by mechanical clean up after such catastrophic events, the Southeast’s remaining longleaf ecosystems face a growing new threat of disappearing.
Like fire, hurricanes are a natural occurrence and the two have historically been the dominant processes in the southern forest ecosystem, Zampieri said.
“We get impacted by two hurricanes a year and they’re impacting the Coastal Plain,” Zampieri said. “Fire, we can manage. Hurricanes we can’t avoid. Then it’s this imminent threat of when will it come?”
On the positive side, they clear out decayed or damaged trees and in the longleaf savanna that means more light on the ground and resources to give biodiversity a shot in the arm.
They also can wreak havoc on the same vulnerable ecosystems, killing off what remains of the longleaf’.
The clean up after a hurricane can also do lasting damage, not to trees, but to the biodiverse understory of grasses and forbs that have intricate root networks intolerant of major disturbances.
Zampieri found that, in the rush to clean up after Michael to remove woody debris ahead of wildfire season, permanent damage was done. The heavy machinery and dragging of trees through the forest associated with salvage timbering left the ground marred and regions where longleaf savannas once dominated, unrecoverable.
“You may have standing trees,” Zampieri said. “But, if you look at the understory after a salvage logging operation, it’s degraded and there is reduced biodiversity, function and ability to carry fire.”
Hurricanes a growing threat to RCWs too
Hurricanes can also have lasting impact on work with endangered species in the Red Hills, particularly the Red-cockaded Woodpecker, which has been the focus of intensive recovery efforts since the 1970s.
While some wildlife is able to hunker down during a storm, the Red-cockaded Woodpecker is not always so lucky. They use old pine trees to nest and sleep in each day. Their cavities take months or years to build and individuals in a family group all need their own cavity. A hurricane can undo that work in a few hours.
The Category 3 level winds experienced from Hurricane Michael were enough to knock down 25 of 150, or 15%, of woodpecker trees on Tall Timbers but the habitat loss was even greater closer to the eye of the storm in the Apalachicola National Forest and Silver Lake WMA in Georgia.
More recently, Hurricane Idalia hit the east side of the Red Hills felling 5 of 40, or 13%, of woodpecker trees at Livingston Place with an additional tree struck from the lighting produced by the storm.
“The lessons learned from these hurricanes is that biologists need to be ready and prepared for these strong weather events. Once trees are knocked down, the woodpeckers will eventually abandon the area in search of available cavities elsewhere, which may be miles away,” said Tall Timbers Woodpecker Conservation Biologist Rob Meyer. “As hurricanes increase in intensity over time, it’s clear that biologists and foresters need to be prepared to clear roads and install artificial cavities to keep the woodpeckers from leaving.”
After a meeting of federal and state agencies at Tall Timbers this year, woodpecker biologists across the region agreed that states prone to hurricanes should maintain caches of artificial cavities and equipment needed. This, combined with a rapid response network of individuals who know how to install these artificial cavities, will be the key to keeping the woodpeckers around after major storms.
Meyer said following Michael there was a reluctance to continue prescribed fire in some areas because the volume of fuel on the ground.
But continuing that process is necessary for the health of fire-adapted plants and animals.
“It’s important to continue to burn, maybe a little more carefully, to keep the landscape from being overgrown with hardwoods.”
Research and adaptive management will continue to be important processes as Tall Timbers and our many partners work to steward land and wildlife in the dynamic coastal plain.