Longleaf pine restoration eases water scarcity in the southeast

(NEWTON, GEORGIA, September 2023) — The southeastern U.S. faces water scarcity issues that concern farmers and conservationists alike. But new research shows that restoration of longleaf pine woodlands can enhance stream flow while conserving an endangered ecosystem—addressing two pressing conservation issues at once.

The study was conducted by a team of scientists from the Jones Center at Ichauway—a non-profit research center in southwestern Georgia—and was recently published in the journal Science of the Total Environment. The team investigated 21 watersheds in rural parts of the southeastern U.S. and found that areas with abundant longleaf pine woodlands had 17% more streamflow on average and 92% higher streamflow during droughts.

Although rainfall is abundant in the southeastern U.S., severe droughts, increased water demands from agriculture, and growing populations can strain freshwater resources and lead to seasonally low stream flow. Low stream flow is problematic because it threatens freshwater wildlife like fish and mussels. At the same time, expanding cities have reduced forest cover and changes in forest management have degraded native southeastern forests, which are home to many rare and endangered species.

The finding that forest restoration promotes stream flow is intriguing to farmers and conservationists because it suggests that two pressing environmental issues, water scarcity and forest degradation, may both be eased by the same solution.

“Forests actually use a substantial amount of water,” says the study’s lead author, Seth Younger, “so when we talk about forest restoration, we don’t mean planting new trees. We mean managing existing forests better, which often means maintaining fewer trees.” Currently, many forests are dense, have a thick midstory, and use water inefficiently. On the other hand, longleaf pine trees use water conservatively, and when restored are maintained as open woodlands with lower tree density and grasses below the canopy that are also water conservative.

“The low tree density and water-conserving species in longleaf pine woodlands means that more rainfall makes its way into the soil and to streams rather than being taken up by trees and understory plants—boosting streamflow, especially during times of drought” says study co-author Steven Brantley.

“Longleaf pine forests were once the most abundant forest type of the southeast, but they have been reduced to less than 5% of their historic range imperiling many associated wildlife and plant species” says ecologist and co-author Jeffery Cannon. “These results are exciting because they show that ongoing forest conservation efforts will also contribute to water conservation in a meaningful way” he adds.

Protecting water resources through forest restoration is feasible as many regional efforts are already underway to promote longleaf pine restoration in the southeastern U.S. One program, America’s Longleaf Restoration Initiative, is working to increase longleaf pine coverage to 8 million acres on private and public lands.

Forest restoration is not the only approach toward addressing water scarcity. The Georgia Flow Incentives Trust, led by the Georgia Water Policy and Planning Center, is seeking to protect streams by testing novel incentives to reduce water use among south Georgia farmers using an innovative auction process. Similar economic incentives in longleaf restoration may help to reach water conservation goals even faster.

“We have long looked to protect water resources by improving agricultural efficiency, but this study lets us see that forest restoration can also help reach that goal” says Brantley.

###

The article, “Impacts of longleaf pine (Pinus palustris Mill.) on long-term hydrology at the watershed scale” was published in Science of the Total Environment found at https://doi.org/10.1016/j.scitotenv.2023.165999

Funding: The study was supported by the US Department of Agriculture, Natural Resources Conservation Service, Conservation Effects Assessment Project-Grazing Lands, under agreement number NR193A750007C002.

Study authors:

• Seth E. Younger, PhD, Jones Center at Ichauway, seth.younger@jonesctr.org
• Jeffery B. Cannon, PhD, Jones Center at Ichauway, jeffery.cannon@jonesctr.org
• Steven T. Brantley, PhD, Jones Center at Ichauway, steven.brantley@jonesctr.org

Media contact

Kevin McIntyre, The Jones Center at Ichauway, kevin.mcintyre@jonesctr.org

About the Jones Center at Ichauway

The Jones Center at Ichauway is non-profit research and conservation center located in Newton, Georgia. The Center’s research, education, and conservation programs focus on ecology and management of southeastern ecosystems, especially longleaf pine. The research program is home to laboratories focusing on forest, plant, wildlife, insect, and stream ecology. Further information can be found on the web site at http://www.jonesctr.org/.