Its sweeping canopy inspired poets, and its strong, straight timber shaped the stories of life in rural Appalachia, until the tree itself became the stuff of fiction. It is now more than a century since the American chestnut tree - once 4 billion strong and an icon of East Coast forests - fell victim to a foreign blight. By 1950, it had virtually disappeared.

Yet people haven't given up on the towering hardwood or slowed efforts to restore it to great swaths of woodland from Maine to Georgia and in the Ohio Valley, where it once reigned through the canopy. Despite the failure of earlier scientific efforts to bring it back, thousands of chestnut aficionados - many based in the Washington area - have new reason for optimism.

By interbreeding the American with its Chinese cousin, tree lovers have created an American chestnut with some resistance to Asian blight and have developed a virus that can be injected into affected trees to combat the fungus. It's a project that shows every sign of promise - with about 25,000 of the new chestnuts planted under the guidance of trained scientists and chestnut devotees.

If the hybrid plantings thrive, some envision huge tracts of strip-mined Appalachia one day being restored with lovely chestnut forests.

"We know we're interbreeding resistance. Now we have to figure out, does it have enough resistance?" said Bryan Burhans, president of the American Chestnut Foundation, which has led the revival efforts.

He said it will take 75 to 100 years to know whether the tree can be reestablished as a mainstay of Eastern forests. But he said he's "very optimistic" about the American chestnut's future.

Some might be intimidated by the prospect of a century-long recovery effort - more than a person's life span, if not a tree's. But as Robert Mangold, who directs forest protection for the Forest Service, put it, "it's a long-term commitment."

And for those on the front lines of the American chestnut crusade, the commitment has become something of an obsession.

"It's really a compelling story. I just sort of got hooked on it," said Kathleen Marmet, who lives near Warrenton, Va., and became involved seven years ago when she lived in Maryland. "This isn't a problem we can solve in our lifetime, but we can do something that has a chance of possibly making a difference."

A fast-growing, hardy tree that thrives on rocky and acidic soil, the American chestnut served as an economic engine for Appalachia. Families fattened livestock with its nuts and used its wood for fuel, railroad ties, fence posts, musical instruments and furniture. It was a fixture along East Coast and Appalachian streets and highways, where its display of fingery white flowers was a springtime delight.

In its heyday, the towering tree not only formed a critical part of the Eastern hardwood forest - researchers think it made up as much as a quarter of the woods' overstory - but also provided inspiration to poets and novelists.

Henry David Thoreau agonized over pummeling a chestnut with a stone to bring down its nuts: "It is not innocent, it is not just, so to maltreat the tree that feeds us," he wrote in his journal on Oct. 23, 1855.