The centurylong quest to save the American Chestnut may soon be over
STATE COLLEGE -- About a mile as the crow flies from Beaver Stadium, where the Penn State faithful gather each fall in search of gridiron glory, stands a chestnut tree.
On this late summer afternoon the chestnut's branches are heavy with burrs -- those unique spiny balls that each protect a single nut. There was a time when any child of the Pennsylvania woods was as familiar with the chestnut burr as an apple, and for many of the same reasons -- good eating, and good for pelting your friends when they're not looking.
In a good year (and this year appears to be good) a single tree can bear more than a thousand burrs -- a prolific bounty that bends this particular chestnut's branches away from the sky and down toward the ground.
The American Chestnut has been called "the perfect tree" for its myriad of uses (food, furniture, lodging, industry, etc.) -- one that carried the people who lived along its range from cradle to grave. It provided a means of the self-sufficiency that became a part and parcel of Appalachian culture that continues today.
The tree was so ubiquitous that its importance could only be underscored by how quickly it would disappear.
The death of the American Chestnut was not the first ecological disaster in North American caused by man nor would it be the last. But it was one of the most well- documented, and one that occurred amid the environmental awakening of the late 19th and early 20th centuries. The speed at which it unfolded made it even more dramatic.
When it was first discovered in 1904 in New York City, the mysterious pathogen was simply that, a mystery -- it would be two years before it had been identified as a fungus and given its common name, the Chestnut Blight.
An entire species of chestnut -- as many as four billion trees -- died as the blight ripped through the Appalachian forests. The species, once so prolific, once such an intertwined part of life in rural Appalachia, was deemed to be functionally extinct by the 1950s.
In the 1920s, federal department of agriculture researchers began interbreeding both Japanese and Chinese chestnut trees with American stock, but they met with mixed results: Hybridized trees were often either not blight resistant enough, did not have the characteristics of the American species, or were stunted or lacked the hardiness necessary to survive outside of a nursery setting.
A second breeding program, begun by the Brooklyn Botanic Garden and later transferred to Connecticut, met with similar results. Eventually, after almost a half-century of effort, both breeding programs were shut down, leaving only remnant stands of crossbred chestnuts in former nurseries (including several in Pennsylvania state forests, where visitors can still come across these old orchards).
For years, it seemed the American Chestnut was doomed to survive in its diminished state, existing only in the memories of those who grew up under its boughs.
The programs' true legacy, however, survived in two trees -- named the "Clapper" and "Graves" trees after their breeders, both of which showed promising disease resistance and characteristics of the American species.
Decades later, those two trees would become the cornerstone of modern efforts to save the species.
http://www.pennlive.com/news/2017/10/american_chestnut_chestnut_bli.html
"The rescue and restoration of American chestnut stands as one of the most difficult, prolonged and complex single-species conservation tasks ever attempted," Steiner and his co-authors write. "However, nine decades after chestnut breeding work began ... the reality of a solution is now less a matter of time and conjecture than has ever been the case before."
https://link.springer.com/article/10.1007/s11056-016-9561-5
= new reply since forum marked as read
Holy cow these were big trees!
you are welcome, your friends at Penn State. 
