For the first time, there was hope for potential recovery of the chestnut tree! With the virus' help, trees had time to react by growing a protective bark layer over the canker. Two decades later, researchers from the Connecticut Agricultural Experiment Station identified what made it so distinct: a virus entwined with the fungus, infecting it and weakening it. Biraghi inspected cankers under the microscope and saw this fungus looked different from any he had seen before. Antonio Biraghi, an Italian pathologist, happened to spot mature chestnut trees with the characteristic orange fungus still growing in an abandoned orchard. Where did this virus come from? We aren't sure, but it was discovered only after the blight had destroyed American chestnut forests and European orchards. Few chestnut sprouts make it to be much thicker than your wrist before the blight re-infects them, unless the tree happens to also host a helpful organism called a hypovirus. Soil microorganisms protect the tree's roots, so the chestnut sprouts again and again where the long-dead trunk stood.
The fungus forms open sore-like cankers on the tree's trunk and branches, cutting off nutrients from the soil. The fungus that causes chestnut blight reproduces both asexually and sexually, creating hundreds of new varieties. They checked each chestnut they found for orange bumps, signs of the blight itself. Yet they hiked into the mountains optimistically, splitting into teams with Forest Insect and Disease Specialist Glenn Taylor. The morning the researchers arrived this fall was drizzly and fog-swirled, making chestnuts hard to spot in the brown understory. Where before about a third of all trees in the Smoky Mountains were chestnuts, today even single spindly saplings are rare.įor the past few years, a research team from West Virginia University, headed by Bill MacDonald and Mark Double, have been collecting samples of the chestnut blight fungus to search for strains of the virus that helps chestnuts. By the 1940s the blight had killed an estimated four billion American chestnut trees nationwide. The chestnut blight, caused by a fungus accidentally introduced from Asia, changed everything. Chestnut blossoms were so thick in spring that the mountains looked coated with snow, and prickly chestnuts piled so deep in fall that people stood up to their knees in the crop. In Great Smoky Mountains National Park, scientists are investigating another type of relationship: a virus that may help trees overcome the deadly chestnut blight.įor centuries, the flanks of the Great Smoky Mountains were crowned with towering American chestnut trees. Crocodiles invite tiny plovers to clean their sharp reptilian teeth and get a meal. Watson and Crick worked together to describe DNA. There are many great partnerships in science. A much rarer sight than it used to be: chestnut leaves turning gold in autumn.
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