The notion of "the forest primeval" exerts a powerful pull on the imagination. We would like to think of the forests in which we hike and hunt as places untouched by humans.

But it isn't so, at least not in much of the United States. "The idea of the untouched forest is a myth all across the country," says Charles Ruffner.

Ruffner, an assistant professor of forestry, studies land-use patterns and ecological conditions over time to understand how old-growth forests have developed and how they can be conserved. His research, and that of others, indicates that the oak-dominated forests of the eastern United States, such as those in Southern Illinois, have been shaped by human activities such as clearing and burning for thousands of years.

John Groninger, an associate professor of forestry and a silviculture (tree cultivation) expert, says of eastern forests, "Disturbances like clearing, grazing, and burning were the rule, not the exception."

How do researchers know that?

Dendrochronology--tree ring analysis--tells them not just growth rates and ages of trees, but also the fire history of a site (fires leave their trace on surviving trees). Field experiments help confirm what tree species do best in the face of disturbances such as fires. Archival research into early historical accounts reveals much about how Native Americans and early European settlers used the forest.

"There's good evidence about fire being used by Native Americans to clear plots in the forest for agriculture, to lower insect populations, and to favor species used for hunting and gathering," says Jim Zaczek, an associate professor of forestry who specializes in forest ecology.

Oak seedlings perish in heavy shade and need a relatively open forest understory, with canopy gaps letting in light. They are well adapted to the fires that once held down the density of competitor tree species. Oaks store more energy in their roots than many other types of trees do, and if seedlings or saplings are affected by fire, they resprout vigorously. Mature oaks also regenerate well after fires, logging, or blowdowns from high winds: they sprout very well from stumps, and the increased light helps them outcompete other species.

As a doctoral student at Pennsylvania State University, Ruffner did dendrochronological studies of old-growth oaks from sites in Pennsylvania and Maryland. Their growth rate, he discovered, was fastest after disturbances in the form of fire and logging of nearby trees. Both types of disturbances resulted in more light and less competition for nutrients.

Today, however, oak-dominated forests in the eastern United States are not in good shape, according to Ruffner, Zaczek, and Groninger. They say that, paradoxically, the forests have been hurt by being left alone, and that if we want to conserve them we must actively manage them.

"Considering their history, just letting these forests go without any type of proactive management doesn't constitute stewardship," Groninger says. "It's neglect."

Maintaining and restoring oak forests will be even more of a challenge because other ecological changes over the past few decades haven't been oak-friendly. Those changes include unnaturally high deer populations and the introduction of rapidly spreading non-native plants, trees, and insects.

"People need to be more educated about the condition of the forest and the consequences of lack of management," Ruffner says. "We know the impacts of past land uses, and we know how we got where we are today.

"We're after forest sustainability."

Ruffner places much of the blame for the decline of oaks in eastern forests on the "Smokey the Bear syndrome": the notion that forest fires are always bad.

The U.S. Forest Service began its highly successful fire suppression campaign, with Smokey at the helm, in the early 1940s. "Fires were seen as reducing forest value and productivity," Ruffner explains. "But by the 1960s and 1970s, foresters were seeing shifts in species, and by the 1980s it became apparent that fire suppression had come back to haunt us."

With the new emphasis on fire prevention and firefighting, fire-susceptible tree species like sugar maple and beech, which thrive in the dim light of undisturbed forests, began shading out oak seedlings. As a result, many eastern forests have few young oaks today to replace the aging ones. When mature oaks die, young maple trees in the forest midstory are shooting up to take their place.

In 1997 Zaczek, Groninger, and Jerry Van Sambeek of the Forest Service's North Central Research Station inventoried the trees in Kaskaskia Woods. This 18-acre old-growth remnant stand in Southern Illinois' Shawnee National Forest has been protected from fire and other disturbance since 1933. Comparing their results to those of a 1935 Forest Service inventory done on this stand, they found that the number of oaks had plummeted and that sugar maples accounted for 60 percent of the trees, up from 20 percent. They also found that the number of tree species growing there had dropped from 26 to 20.

Ruffner, Groninger, and master's students Trevor Ozier and Saskia van de Gevel recently surveyed hundreds of tree monitoring plots set up at Trail of Tears State Forest some 20 years earlier. They determined that the number of oaks in these plots, which had experienced no fires in that time period, also had dropped dramatically. "What I found shocking was that it was happening so quickly," Groninger says.

James Fralish, a professor emeritus of forestry at SIUC, has documented succession by sugar maples at many other sites in the Shawnee, and the same pattern is occurring in many other eastern forests.

Is this development undesirable? In the end, that depends on what we want our forests to be like. But Ruffner, Groninger, and Zaczek say that it has environmental disadvantages. "The forest will remain," says Groninger, "but it will become something different."

Oaks are a keystone species in eastern forests, meaning that they support many other species directly or indirectly--from deer to small mammals to migrating neotropical songbirds. As oaks decline due to reduced disturbance, certain other species are likely to decline as well. "Generally, biodiversity goes down as sugar maple and beech replace oak," Ruffner says.

Zaczek explains that maples "tend not to be as important in supporting wildlife. Oaks drop seed in the fall, just before the dormant season, when many animals need a food source.

"A proportional loss of oaks leads to a proportional loss of other native species that depend on them. There are so many interrelationships out there. If we accept the loss of oak, we have to accept the loss of other things, some of which we may not anticipate or entirely understand."

Some species have already suffered from lack of disturbance in the changing forests.

To take one example, ruffed grouse have gone locally extinct in Southern Illinois in part because they need the cover and forage provided by young tree stands in regenerating areas. To take another example, timber rattlesnakes, which play an important role in the environment because of the number of rodents they eat, are declining because they need openings in the forest canopy to maintain their body heat.

Ruffner, a fire ecologist, has another concern about the switchover from oaks to maples. When forests go for decades without burning, they fill up with fuel--dead wood, thick duff (decaying vegetation on the ground), and choked understory growth. Such conditions set the stage for catastrophic wildfires that ravage forests.

The need for fuel reduction is most critical in the drought-afflicted western states, which have seen many such fires in recent years. Despite our wetter climate, however, Southern Illinois experiences dry spells too. Sugar maples are more drought-susceptible than oaks and will add proportionately more to the fuel load during dry years, Ruffner says. He worries that an extended drought could result in damaging wildfires in this region, where so many people live in close proximity to forestland.

Smokey the Bear ("Only YOU can prevent forest fires") remains a useful warning symbol for the public. Too often, catastrophic fires get started due to carelessness with cigarette butts or campfires. What the forest needs instead is the right kind of fire in the right place at the right time. Prescribed burning, a tool that foresters are increasingly using for land management, treats a site for restoration purposes under specific conditions, so that the fire does not get out of control or burn too hot.

Each year Ruffner teaches a popular course that allows students to gain their "red card": national certification as wildland firefighters. Those students, called the Saluki Fire Dawgs, help battle forest fires in the West each year. But they also serve as Ruffner's fire crew to carry out prescribed burns for regenerating oak on public and private land in Southern Illinois.

The Fire Dawgs help Ruffner collect data on oak regeneration patterns in burned areas of the forest, and they're working with him to develop fuel models: standardized classifications of forest fuel based on the types and quantities of burnable foliage. Knowing an area's fuel model can tell foresters how hot a fire could get and how fast it could spread--information crucial in controlling prescribed burns.

There are 13 commonly used fire models in the United States, but most were developed out West. With funding from the U.S. Forest Service, Ruffner and his students are now working on fuel models specific to Southern Illinois for land managers' use.

At several sites throughout the region, Ruffner and Groninger and their students are comparing the effects of repeated prescribed burning, selective cutting, a combination of the two, and no treatment. The research is funded by the Illinois Department of Natural Resources and the Wild Turkey Federation.

The team has found that for effective oak regeneration, burns must encompass at least 50-60 acres. "We started with 5-acre plots, but the deer just moved in and ate up all of the oak seedlings," Ruffner says. "The larger the treatment area, the more we overcome the deer's appetite."

Prescribed burns aren't always sufficient to restore succession by oaks rather than by maples, that project has shown. Fire has been suppressed for so many decades that maple trees often are big enough to survive the burns. That's why the researchers are also studying the effectiveness of thinning the forest in some areas, by cutting trees less than 10 inches in diameter to give oak seedlings a chance to get going.

Some areas, they say, may require larger-scale cutting to maintain an oak-dominated forest. "There are places we shouldn't touch, but cutting down some trees can be part of regenerating a forest," says Zaczek. He, Groninger, and Ruffner concur that, done judiciously, logging in eastern forests can be a plus both for long-term forest health and for local economies.

The issue of forest management is not restricted to public lands, which account for just a fraction of eastern forests. As Ruffner notes, Illinois boasts some 4 million acres of forest. The Shawnee, the only national forest in Illinois, has less than 3 percent of that acreage.

"How private landowners manage their own land is really critical," Groninger says, especially since private timber stands are much more likely to be logged at some point. Since some tree harvesting in eastern woodlands would be beneficial, and in places crucial, for conserving or regenerating oak forests, this offers an opportunity to combine ecological restoration with badly needed economic development, the three researchers say.

Helping landowners maintain their oak forests for periodic timber harvesting can create jobs while being good for wildlife. It also would reduce the need for importing wood from countries where uncontrolled logging is resulting in environmental degradation.

But it needs to be done right. Harvesting trees in an ecologically sound way, with an eye to oak regeneration rather than one-time profit, is what makes the enterprise sustainable. It's economically and environmentally prudent for the long haul--and, says Groninger, "If it makes economic sense, a lot more people will do the right thing ecologically."

The SIUC researchers' focus, however, is not on timber production but on conserving oak-dominated forests and restoring them where they have been destroyed for decades. On such sites, planting is essential because no seed bank remains to regenerate the trees.

In a joint project, Groninger and Zaczek are evaluating the status of The Nature Conservancy's efforts to restore 1,000 acres of floodprone farmland in the Grassy Slough area of Southern Illinois to bottomland oak forest. And in a project funded by the U.S. Department of Agriculture (USDA) and Black Beauty Coal Company, Groninger and his students are experimenting with different types of tillage and herbicide treatments to see which work better for forest restoration on reclaimed mine land.

Zaczek recently remeasured oak trees planted 16 years ago in a Pennsylvania experiment comparing the survivability of acorns and different types of nursery stock under various cultivation techniques. The goal was to see what kind of stock would get trees as quickly as possible to four or five feet tall, a height threshold where the chances of survival go way up because it is above deer browsing. "The first few years are critical," Zaczek says.

Among other things, he found that one-year-old oak seedlings from nurseries don't survive much better than acorns do; two-year-old potted stock does best but is too expensive; high-quality two-year-old bare-root stock (no soil ball around the roots) is the best all-around choice; and intensive culturing (such as top-cutting the seedlings before planting, which can result in higher growth rates) helps, but not significantly. Zaczek and his students also have worked extensively with oak propagation techniques needed to produce nursery stock.

The USDA has funded other research by Zaczek to improve acorn survivability for oak regeneration. At various upland and bottomland forest sites in Southern Illinois, he and graduate student John Lhotka used a small tractor with a disc harrow to incorporate acorns a couple of inches into the soil in the fall. That protected the acorns from being eaten, drying out, or freezing because of lack of snow cover.

Incorporation made a huge difference the next spring, they found. Up to 14 times more acorns germinated with the treatment than without it. The more acorns that germinate, the more seedlings that will survive browsing deer.

The tractor also knocked down many of the maple saplings on these sites, which will give the oak seedlings a better chance to survive to midstory height. The midstory must have enough oak trees to outcompete maples for a place in the canopy as the big oaks die off.

Zaczek would like next to test the use of incorporation followed by prescribed burns. "We've found that when acorns germinate on the soil surface, they won't resprout if a fire comes through," he says.

Regenerating oak forests, he warns, "may be a several-step process, and it may not be cheap." Especially where public lands are involved, people must be patient: "Forests are not pleasant to look at in the first few years after logging or burning."

Or, as Groninger puts it, "Forests develop over time periods that are inconveniently long for people. Our frame of reference is too small."

He adds, "Our hope is to maintain diversity--to maintain the oak ecosystem in at least certain areas so that our options will be open for the future."

--by Marilyn Davis, ed.