After recently receiving DNA test results indicating the trees are indeed 100% American chestnut, Rosenfeld is in talks with state officials to use his seedlings in repopulation experiments designed to bring the wildlife-friendly tree back to public lands.

“You could kind of color my position as cautiously optimistic,” said Justin Clark, the Pennsylvania Game Commission’s wildlife habitat group manager for Lebanon and Dauphin counties.

Gameland plantings are still at least two years away, Clark said, but tentative plans involve a 200-tree grove on a two-acre plot near Mount Gretna, Lebanon County.

“We’ll get good data on the percent resistant,” Rosenfeld said. “If we put out 200 trees, that’s statistically significant.”

Determining success could take a decade, as it takes about that long for chestnut trees to start producing nuts and to determine if trees have enough resistance to survive the blight.

“For the natural resources field, it’s important to frame our time references not in human years because we tend to be so impatient,” Clark said.

Varying approaches to recovery

Those seeking to restore chestnut forests have taken three approaches: selective breeding to cultivate blight resistance in surviving 100% American chestnut trees, cross-breeding to create a hybrid with blight-tolerant Chinese chestnuts and genetic modification to induce blight resistance.

Conflict among supporters of different recovery approaches ignited late last year when State University of New York College of Environmental Science and Forestry researchers were forced to admit they had mixed up two genetically modified strains within their study and the American Chestnut Foundation declared the study’s results too poor to continue funding.

Rosenfeld is a believer in selective breeding. “It’s slow, relatively speaking, but it works,” he said.

His backyard grove of 50 chestnut seedlings, bred from blight survivors in West Virginia, has produced five mature trees and 5,000 third-generation seedlings.

Rosenfeld’s nursery, Go Native Tree Farm in West Hempfield Township, sells those seedlings.

Other local conservationists are following the cross-breeding approach, with the Lancaster Conservancy providing space in the Martic Township Clark Nature Preserve for American Chestnut Society studies.

The trees were once a key source of food for wildlife, indigenous people and early American settlers.

“It’d be really great to restore them,” said Keith Williams, the conservancy’s vice president for engagement and education.