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Compass July 2006
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Compass is a quarterly publication of the USDA Forest Service's Southern Research Station (SRS). As part of the Nation's largest forestry research organization -- USDA Forest Service Research and Development -- SRS serves 13 Southern States and beyond. The Station's 130 scienists work in more than 20 units located across the region at Federal laboratories, universites, and experimental forests.

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Issue 6

What Can Experimental Forests Teach Us About Afforestation?

A Tale Told by Two Forests

Scientists predict that the South’s forest acreage will remain stable over the next several decades, with losses from urbanization in the Atlantic States offset by tree planting on abandoned agricultural lands further west. Restoration of bottomland hardwoods on Lower Mississippi Alluvial Valley lands will play a large role in guaranteeing the success of these predictions. Bottomland hardwood restoration is not just planting trees, but rather a process that involves selection of species, thinning, and protecting against diseases and insect infestations.

Two experimental sites, the Delta Experimental Forest and the Sharkey Research and Demonstration Site, have provided scientists with ideal conditions for studying bottomland hardwoods and developing tools and guidelines for restoration by landowners.

The Delta Experimental Forest

The Delta Experimental Forest is a State-owned 2,600-acre property in Washington County, MS, that was established for research in a 1945 agreement with SRS. Drained by a network of ditches, it was a working forest whose timber receipts paid for a crew of laborers and technicians to establish and maintain research studies.

Research during the first 30 years or so involved thinning, developing methods for growing quality southern hardwoods, evaluating results of efforts to improve eastern cottonwood clones, and studying the progression of heartrot diseases and the life cycles and impacts of insect borers. Later studies included determining the causes of oak decline and investigating red oak-sweetgum stand dynamics.

These studies provided much of what we know about species-site relationships on the poorly drained, less fertile soils deposited by the Mississippi River. In addition, several eastern cottonwood clones—selected during the 1960s and 1970s by geneticists at the SRS Center for Bottomland Hardwoods Research and still used throughout the South by forest industry, government agencies, and some foreign countries—were tested in the Delta Experimental Forest.

The 1970s saw a change in allocation of harvesting revenues to other State priorities, resulting in a decline in both forest operations and new studies. By the mid-1990s, heartrot had degraded many older trees. Several ice storms struck the forest in the 1990s; the worst in February 1994 severely damaged the crowns of most canopy trees. Many of the stands were cut in the late 1990s to regenerate degraded forest stands. Oak seedlings were planted to supplement natural oak regeneration.

Current research concentrates on wildlife, with scientists beginning a new study to look at insect food for the ivory-billed woodpecker. The study involves the establishment of some 200 cages to hold bolts of wood cut from trees infested with wood-boring insects. As insects emerge from the wood, they will be identified, quantified, and further studied.

The Sharkey Research and Demonstration Site

Late in the 20th century, new legislation enacted to stimulate the conversion of agricultural land to forestry and a desire to develop more ecologically oriented restoration alternatives prompted scientists to seek a site for new management studies. Fortunately in 1995, the Yazoo National Wildlife Refuge established a bottomland restoration site on abandoned farmland in nearby Sharkey County. Like the Delta Experimental Forest, the Sharkey Site consists of poorly drained, clayey soils typical of slack water areas along the Mississippi River. And like the abandoned agricultural land throughout the area, the Sharkey soils tend to form deep cracks that close when wet. For these reasons, research findings from the Sharkey Site can be applied almost anywhere in the lower Mississippi Valley.

Collaborators at the Sharkey Site include scientists and managers from Federal Agencies—U.S. Fish and Wildlife Service, the USDA Forest Service and Natural Resources Conservation Service, the U.S. Geological Survey, and the Army Corps of Engineers—State agencies, universities including Mississippi State and Mississippi Valley State, nongovernmental organizations including the National Council for Air and Stream Improvement, and private industry including Crown Vantage Corporation and International Paper Company.

Photo of a cottonwood plantation

These 1 to 2-year old cottonwoods are ready to provide shelter for slower growing Nuttall oak. Grown together, they provide the structure for economical afforestation of the Lower Mississippi Valley. (photo by Bill Lea)

The most prominent of the new restoration studies contrasts several options for interplanting cottonwoods with red oaks: inexpensive nonintensive practices, conventional practices familiar to managers, and intensive practices that address multiple ecological objectives. Another study of natural regeneration focuses on patterns of invasion by trees and shrubs. And in a large fenced area, new techniques are being developed to establish black willow on harsh wetland sites; because of its rapid growth, this species could be useful in addressing climate change by removing and storing carbon.

One unique component of the infrastructure at the Sharkey Site is an impoundment of compartments that can be independently flooded and drained for studies on pondberry, an endangered forest shrub, and other woody plants.

In publications, tours, new technologies, industry demonstrations, and training for students, scientists at the Sharkey Site continue the work started at the Delta Experimental Forest. Their results show the feasibility of establishing a multispecies plantation that promotes rapid stand development, diverse ecological values, and multiple management objectives—the basic components of a sustainable model for restoring bottomland hardwoods in the Mississippi Delta.

For more information:

Ted Leininger at 662-686-3178 or

Photo of Cottonwoods
Landowners can visit the experimental plots set up at the Sharkey Research and Demonstration Site to look at how different plantings perform over time.
(Photo by Melissa Carlson)