Fire, like rain, is vital to the shaping of a forest

On the Bay

Intro: A Frostburg State biologist points out that even the greenest landscape may contain evidence of a long history of burns.

May 26, 2000|By Tom Horton | Tom Horton,SUN STAFF

SWANTON -- One of the most thought-provoking spots in Chesapeake country is a lordly patch of ancient forest here in Garrett County.

It lies at the edge of the bay's watershed, or drainage basin. Farther west, the Eastern Continental Divide shrugs off rainfall toward the Gulf of Mexico.

The crackling burn of a forest fire, hot and orange and smoky, would be the last image to come to mind here today. The deep woods are cool and green and moist -- trees so tall and leafy a thundershower pelts the forest canopy for a half-minute before misting onto hikers below.

Still, fire in the forest is on our minds because of Los Alamos, N.M., where a blaze set by the National Park Service ran amok, consuming part of the town.

And it's on our minds here because of some intriguing detective work carried out in this forest on the slope of Big Savage Mountain by Durland Shumway, professor of biology at nearby Frostburg State University.

For Shumway, the giant oaks that dominate the woods here, ranging to four centuries old and four feet in diameter, provide a rare lens for peering into the history and ecology of the landscape as far back as the early 1600s. This forest is true old growth -- never cut by the European civilization that logged or cleared most of the Eastern United States. Covering no more than a few hundred acres, this is the biggest remaining chunk of old growth in Maryland. It seems the epitome of changelessness, an undisturbed nook.

But that's not what Shumway has found. From their size and age, as determined by counting the growth rings in fallen specimens, it's obvious that the oaks -- black oaks, white oaks, red oaks and chestnut oaks -- have persisted for centuries.

But it's just as obvious that the future forest here is already on the way to something quite different -- there is a remarkable absence of little oaks in the understory, Shumway observed. Instead, maples and black birch seem to be most common. There could be several reasons for that, he notes, including heavy browsing by deer.

They prefer little oaks over little maples and birches. But the biologist, when he analyzed the growth rings of ancient oaks, found another compelling force at work -- fire, and fire that has occurred so routinely and frequently it might be as essential as rain to shaping the forest.

From fire scars detectable in the growth rings, Shumway has constructed a 400-year record that shows fires, some big, some small, swept the slopes of Big Savage Mountain about every eight to nine years. It happened this way throughout the 1600s and the first half of the 1700s, before the first European settlers began moving in around 1750.

Whether the source of the fires was lightning or deliberate burning by Native Americans, or a combination, is speculative. It is known the Indians burned forests routinely to open the understory for hunting, and also to encourage growth of edible and medicinal plants on the forest floor.

Shumway hopes an archaeological dig in the Garrett County old growth will shed light on this part of the mystery. After settlement around 1750, the evidence of burns -- just as frequent -- continues into the 20th century. These could have been started by sparks from a local railroad, an iron furnace, loggers and lightning.

But then, halfway through the 1900s, the modern era of fire suppression policies on government lands (the trees are in Savage River State Forest) assert themselves, and fires fall off dramatically. And therein, Shumway suspects, might lie the secret of the old forest here -- that for all the moist green image it presents, it has been fundamentally a pyrogenic landscape.

Young oaks in the understory tolerate fire, while maples and birches don't. Without regular burning -- some of the old trees show scars from flames that leapt 15 feet high -- the oaks might not be able to compete. More detective work should afford an even longer-range perspective -- plugs of sediment cored from a wetland atop Big Savage are being analyzed for tree pollen preserved in the muck, to provide an 8,000-year record.

The cores appear to contain charcoal, signifying that fire was always present. The implications range from the mystical to the practical. Fire and rain are two sides of the same coin, the former no more an unnatural disturbance than the latter.

Fire is just another fierce, wide-ranging beast, like the cougar and the wolf, that we have eliminated from the landscape. To reclaim the rich acorn and hickory nut regime so productive of wildlife in old growth, and bring back its rich diversity of plants and animals, will take more than just waiting 400 years. It will take active management, like burning.

And in light of the liability issues raised at Los Alamos, there might be places where we need to warn those enamored of a home in the forest that they must expect fire -- just as we warn those who would settle on ocean beaches in the path of hurricanes, or along rivers in the way of floods.

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