 Soon after that, though, the American chestnuts were nearly wiped out by chestnut blight.The discovery of the blight fungus on some Asian chestnut trees planted on Long Island, New York, was made public in 1904.Within 40 years, the nearly four billion-strong American chestnut population in North America was devastated; only a few clumps of trees remained in Michigan, Wisconsin, California and the Pacific Northwest.