Mizunara oak, known scientifically as Quercus mongolica var. crispula, is a species of oak tree native to Japan, Korea, and parts of China. This tree is notable for its unique, porous wood, which is highly valued in the production of Japanese whisky barrels. The wood's characteristics contribute to the distinct flavors and aromas of the whisky aged in these barrels. The mizunara oak can grow up to 25 meters tall and has a broad, spreading crown. Its leaves are deeply lobed, and the tree produces acorns that are an important food source for wildlife. Due to its slow growth and specific habitat requirements, mizunara oak is considered a vulnerable species.