Walnut trees, genus Juglans, are plants which mostly grow in the Northern hemisphere.

They can reach 10~40 metres (30-130 ft) in height.

Walnut trees grow from Europe to the Himalayas and southwest China. In the Americas, walnut trees are found all the way from Canada to Argentina.

They are used for timber. The wood is very hard, and dark in color. It is mostly used for making furniture. The fruit is eaten and can be used for making oil. The fruit of Juglans are called walnuts. Material of the walnut's outer casing was used by Native American tribes to poison fish.