Tramping along a forest path after a spring snow storm, Bruce Graham brims with excitement over his discovery of a cluster of thriving American sweet chestnuts, one of the rarest trees in the world.
In a forest hollow outside this farming community in Canada's tobacco-growing belt, Mr. Graham rushes to a solitary American chestnut grown so large around he'd have difficulty getting his arms to encircle its trunk.
"This is something you just don't see," effuses Mr. Graham, a nurseryman for the Grand River Conservation Authority, patting the furrowed and slightly green-tinted trunk of this arboreal rarity.
For many arborists, finding a healthy American chestnut tree in the wild is akin to a paleontologist stumbling upon a living dinosaur. For decades, the American chestnut, not to be confused with the poisonous and unrelated horse chestnut, has been considered practically extinct, the victim of one of the greatest ecological catastrophes to hit a forest environment in modern times.
But the discovery of a small remnant population of four mature trees in Burford and at several other locations in Southern Ontario since the late 1980s is giving new hope that chestnuts, a species almost destroyed by human carelessness, may be able to avoid extinction.
Until 1904, the chestnut tree was an abundant and familiar North American sight, dubbed the king of the trees for its towering size. But that year, a deadly and tenacious blight started to destroy chestnuts in the New York area. Within decades, the disease, carried on infected plants from Asia, devastated chestnuts throughout their normal range from southwestern Ontario to Georgia. A mind-boggling 3.5 billion trees were killed, almost 100 per cent of the population.
Currently, a few other trees remain in isolated pockets outside the normal growing area, in places such as Nova Scotia, where the blight hasn't reached. Maintaining these trees -- which are thought of as something akin to zoo specimens -- is not considered as important as finding ways to return the species to the forest setting where it was naturally found.
Scientists believe that all American chestnuts will die if exposed to enough of the blight, making something of a mystery the discovery in Burford, just west of Brantford in southwestern Ontario, of apparently healthy trees in an area where chestnuts were historically known to be growing.
Spread by the wind and birds, the blight causes a canker that girdles the trunk and causes a slow death by constricting the flow of a tree's life-giving sap to everything above the point of infection.
Mr. Graham speculates that these chestnuts may have gained some immunity to the blight because the trees are near white pines. He said some unknown factor about the two tree species growing in proximity may be aiding the chestnuts, although researchers reject this theory. "Most of the higher-up professors think I'm crazy," Mr. Graham says.
In recent years, Mr. Graham has been assiduously gathering nuts from the trees, found on a private woodlot, and planting them in the authority's nursery. The Grand River Conservation Authority offers the seedlings for sale, allowing the public to aid in the survival of the species by creating a larger natural population of the threatened trees.
To date, thousands of trees have been planted, and Mr. Graham has yet to hear reports of any of his saplings dying from blight.