- [b] [[Chesnut Trees Made Up 25% of the Forests in the Eastern US Before Chestnut Blight Killed Almost All of Them. They Rained... by reddit]] - [l] [[2021.07.21a A single fungus can destroy an entire way of life]] The American chestnut was one of the most important trees in the eastern hardwood forest. They were an important source of food for wildlife and humans alike, and their wood was prized for its strength and rot-resistance. But in the early 1900s, a fungal blight spread through the population, killing an estimated 3.5 billion American chestnut trees. The American chestnut was not the only tree to suffer from this blight – other species like the European chestnut and the Chinese chestnut were also affected – but it was hit the hardest. The fungus, called _Cryphonectria parasitica_, attacks the tree through wounds in the bark, causing cankers to form. The cankers eventually girdle the tree, cutting off its water and nutrient supply and killing it. The American Chestnut Foundation is working to bred blight-resistant American chestnut trees, and they hope to have them ready for planting in forests within the next few years. In the meantime, there are a few isolated populations of American chestnuts that have managed to survive – mostly in areas where the soil is too rocky for the fungus to take hold. These trees are carefully monitored.