By C. Jane Anderson, PhD candidate, Wildlife Ecology & Conservation Dept.
If you’re a Floridian, your backyard used to be on fire. Frequently, as a matter of fact. This is because, historically, nearly the entire southeastern U.S. was covered in an ecosystem known as longleaf pine forest. This ecosystem not only thrives with fire, it needs it to survive. Although the longleaf pine was once the reigning champion of southeastern trees, it is now in urgent need of conservation planning and human intervention to survive.
Longleaf Pine Forest Ecology
Longleaf pine forests are dominated by their namesake, the longleaf pine (Pinus palustris). This unique species grows to 30-35m (98-115 ft) and lives for over 300 years. Visitors to longleaf pine forests will notice the tall longleaf pine trees, abundant grasses, and a lack of midstory (or middle-sized trees). These forests are considered fire-dependent. Frequent, small fires clear the understory (or lowest layer) of the forest. Longleaf pine saplings and several important grasses are specially designed to survive the blaze. These fires kill other small trees, however, which makes room for more longleaf pines. The longleaf saplings need an abundance of light to mature, so clearing out the other trees allows them to thrive. When these forests dominated the landscape, frequent, small fires caused by lightening controlled the system. Now that longleaf pine forests have been reduced to less than 5% of their original range, humans must create prescribed fires to mimic the natural system.
Where Have all the Longleaf Pine Forests Gone?
Prior to European settlement, nearly the entire southeastern U.S. – approximately 75 million acres – was covered in longleaf pine forests. When early settlers arrived, they quickly noticed many economic benefits of longleaf pines. Resin, turpentine, and timber harvested from the longleaf pines were sold by merchants and used extensively by early U.S. Navy fleets. Eventually most of the longleaf pine forests were clear-cut. Some were maintained as forests for the timber industry but replaced with faster-growing species such as the loblolly pine (Pinus taeda) or slash pine (Pinus elliotti). Others were replaced with agriculture, suburban areas, or cities.
Why it Matters
Some wildlife species are habitat generalists, meaning they can survive in a variety of habitats. Others are habitat specialists, meaning they require very specific habitat types. Longleaf pine forests are home to numerous habitat specialists, including many that are threatened or endangered. These include Gopher tortoises (Gopherus polyphemus) and red-cockaded woodpeckers (Leuconotopicus borealis), as well as more than 30 species of amphibians.
In addition to wildlife conservation, longleaf pine forests provide many ecosystem services and economic benefits. Because the trees are long-lived with long growth periods, they act as carbon sinks (i.e., they remove large amounts of carbon from the atmosphere, thereby mitigating air pollution). They are used to produce timber, resin, and pulp; these products can be obtained from other pine trees as well, but longleaf pines are the preferable choice because they are very resistant to disease and other natural disasters. Additionally, they have historic and cultural significance in the southeastern U.S.
Steps to Recovery
Scientists now understand the importance of protecting longleaf pine forests, as well as restoring habitats where they were historically found. America’s Longleaf Restoration Initiative is multi-state collaborative effort which aims to restore over 4 million acres of longleaf pine forests in the southeastern U.S. by the year 2025. Researchers and land managers must now determine the best methods to make this happen. Through her work at the Joseph W. Jones Ecological Center, Dr. Kay Kirkman is helping to take on this challenge.
The Joseph W. Jones Ecological Center is located on Ichauway, a 29,000 acre tract of land in southwest Georgia. Ichauway was established as a quail hunting preserve in 1920 by Robert W. Woodruff, an avid outdoorsman and hunter. Mr. Woodruff understood the importance of maintaining longleaf pine forests for quail habitat. In 1991 the Joseph W. Jones Ecological Center was established on Ichauway, with the aim ”to understand, to demonstrate and to promote excellence in natural resource management and conservation on the landscape of the southeastern Coastal Plain of the United States.” Today, Ichauway is predominantly longleaf pine forest, interspersed with patches of other forest types. This provides the perfect landscape for Dr. Kirkman to conduct her research to understand the best methods for restoring, conserving, and protecting longleaf pine forests.
Research and The Future of Restoration
Some suggest simply clear-cutting forests, then planting longleaf pine saplings is the most effective method to restore longleaf pine forests. Dr. Kirkman led a research team to evaluate an alternative method: instead of clear-cutting, they created gaps in the canopy of trees using herbicides, mechanical methods (e.g., mowing, cutting trees), and controlled burns. These gaps provided the light needed for pine saplings to grow. However, as Dr. Kirkman predicted, the efficacy of this method is dependent on the history of the land (e.g., whether it had been previously burned). This led to an important implication in longleaf restoration: the best method to restore a forest is dependent on the history of the forest. Land managers interested in restoring their forests to longleaf pine systems can use this research to develop restoration plans specific to their land. Dr. Kirkman published these findings in 2013 in the journal Ecological Applications.
In addition to her ecological research, Dr. Kirkman is involved in education and outreach for private landowners, public land managers, and commercial operators to encourage longleaf pine restoration. By demonstrating restoration for land managers, she hopes to create a demand, and therefore a market, for longleaf pine saplings. She has partnered with seed growers across the southeastern U.S. to supply this market.
Dr. Kirkman’s work embodies an innovative approach to conservation. By integrating research, education, and outreach, she is helping develop sustainable strategies to protect and restore longleaf pine forests. You may be grateful your backyard is no longer on fire, but all southeasterners will benefit from the restoration of this important ecosystem.