The chestnut is the most useful tree in the world.

There are 4 major species
American Chestnut (Castanea dentata)
European Chestnut (C. sativa)
Chinese Chestnut (C. mollissima)
Japanese Chestnut (C. crenata) and 9 less important species of the genus Castanea in the world. Considering the importance of chestnuts as a high carbohydrate food source for thousands of years, and the beautiful, rot-resistant wood that is used from everything from vineyard stakes, fence posts to siding and bridge timbers, and was a major source of tannin for tanning leather, is there any tree that provides this range of uses and value? Oaks, pines, and fruit trees each provide single uses for timber or food, and many have a larger total monetary value for the that use or crop than chestnuts. However, no tree species in history has offered such a wide range of uses or importance. It is little wonder that chestnuts have been grown by every major culture, and transported in conquests and explorations to every continent where it could be grown.