Water defines the Mississippi Delta, an alluvial plain in northwest Mississippi. The Delta is sandwiched between the Yazoo and Mississippi Rivers, and a network of levees and pumps aim to keep the land dry enough for habitation and agriculture. In 2019, however, historic flooding left fields inundated for months.
USDA Forest Service scientists have served the region since the 1930s by providing sound science for land managers.
“The SRS Center for Bottomland Hardwoods Research has worked with Delta National Forest for decades on all aspects of bottomland hardwood management,” says Todd Sewell, the Delta’s new district ranger. Sewell recently joined the Forest Service after decades of experience with other USDA programs, including Natural Resources Conservation Service.
The Delta National Forest is the only 100 percent bottomland hardwood forest in the National Forest System. And the Center is the only Forest Service laboratory conducting research in bottomland hardwood ecosystems and associated stream systems.
Early Center research focused on hardwood regeneration, a critical need after decades of intensive logging. Center scientists still conduct silvicultural studies, but over the years, their focus has broadened.
Today’s stakeholders include wildlife organizations, universities, state and federal land management agencies, private landowners, farmers, forest industries, and others. In April, about 70 of these stakeholders gathered for the 66th annual meeting of the Southern Hardwood Forest Research Group. It was also the 9th annual Dr. John Adams Student Poster Competition, and many students participated.
Threats to the bottomland hardwood resources were the theme of the meeting, and speakers included:
- Nancy Loewenstein, extension specialist at Auburn University, discussed invasive riparian plants like Chinese tallow (Triadica sebifera). Unfortunately, Chinese tallow is an attractive tree, and some continue planting it, despite its ability to invade natural areas, form dense monocultures, and harm frogs, toads, and their tadpoles.
- Andy Ezell, retired forestry department head of Mississippi State University, discussed the logistics of controlling plant invasions. While backyard invasions can often be managed with repeated hand-pulling, foresters and those who manage large areas often rely on herbicides. Herbicides are sometimes most effective in certain seasons – for example, Chinese privet (Ligustrum sinense) is semi-evergreen, so herbicides are best applied when native vegetation is dormant.
- Brian Murphy, wildlife biologist and CEO at Quality Deer Management Association, discussed chronic wasting disease. CWD is not known to affect humans, but is always fatal to deer and is spreading rapidly through the U.S. It has been detected in 24 states including Arkansas, Mississippi, Tennessee, Texas, and Virginia.
- Diane De Steven, emerita research ecologist at the Center, discussed the benefits of wetland conservation practices in croplands and the challenge of estimating those benefits. Her work is part of the Conservation Effects Assessment Project, which aims to quantify the effects of conservation practices and develop the science for managing agricultural landscapes.
- Ying Ouyang, research hydrologist at the Center, discussed groundwater depletion, a serious concern across the globe and in the Mississippi Delta, where average groundwater levels have declined by more than 20 feet since the 1970s. Irrigating crops with water from farm ponds instead of groundwater is one mitigation strategy, as are afforestation and reforestation.
- Emile Gardiner, research forester at the Center, discussed oak silviculture in the Delta, placing his extensive research into a historic context. Since 1956, researchers have observed that sunlight is a critical factor in oak seedling development. The shelterwood method of regeneration can be used to develop oak seedlings to a competitive size before a final release, but managers should monitor development of the reproduction between initial and final harvests.
- Frank Howell, executive vice president of the Delta Council, gave a status report on Congressional support for hardwood research.
- Robert Progar, national entomology and pathology program lead at the USDA Forest Service, discussed invasive insects and diseases, as well as control methods.
Invasive plants, insects, and diseases are a scourge at every scale – local, regional, and global. Center scientist Dan Wilson, a research plant pathologist, is developing new electronic-nose technology methods for noninvasive, early detection of white-nose syndrome, a fungal disease that is devastating bat populations across the U.S. “Wilson’s e-nose research is poised to really take off,” says Progar. “Electronic-nose technology has applications in so many fields – forestry, agriculture, medicine, pharmaceuticals, and more.”
Center scientists also study threatened and endangered species, including pondberry, mussels, and crayfish.
“It’s very unique that we’re detecting white-nose syndrome, addressing forest management, and studying aquatic and terrestrial fauna in bottomland ecosystems in the mid-South,” says Center project leader and research plant pathologist Ted Leininger.
“We’re also providing the science and expertise for afforesting marginal agricultural lands in the alluvial valley,” says Leininger. “Some of these hardwood plantations are now decades old, and landowners need to know how to manage their stands for a sustained supply of timber and wildlife.”
The Center’s mission is so compelling that many of its retirees stay as emerita and emeritus researchers. Including them, the Center has 15 scientists, organized into four teams:
- Ecology of Aquatic and Terrestrial Fauna
- Ecological Processes and Restoration
- Regeneration and Reproductive Biology
- Stand Management and Forest Health
Over the years, the Center has become part of its local community and economy, as evidenced by the Southern Hardwood Forest Research Group. “These annual meetings build cohesion into the research by bringing all the stakeholders and interested parties together,” says Progar. “It’s so helpful and beneficial that you can’t put a value on it. It’s of critical importance.”
For more information, email Ted Leininger at email@example.com.