Betula schmidtii

Betula schmidtii, the iron birch or Schmidt's birch, is a species of flowering plant in the family Betulaceae. It is native to Manchuria, Korea, Primorsky Krai of the Russian Far East, and Japan. A tree reaching 30 m with nearly black bark, its wood is so dense that it does not float, and is used where a tough, durable material is desired.