 The American chestnut also contains more nitrogen, phosphorus, potassium and magnesium in its leaves when compared to other trees that share its habitat.This means they return more nutrients to the soil which helps with the growth of other plants, animals, and microorganisms.Once an important hardwood timber tree, the American chestnut suffered a substantial population collapse due to the chestnut blight, a disease caused by an Asian bark fungus ("Cryphonectria parasitica", formerly "Endothia parasitica").