What is a willow tree used for?

A willow is used mostly as an ornamental decoration in a designed landscape. It has very little shade value and needs a good water supply.One willow tree is famous for its contributions to medicine. Salix alba, or white willow has bark which has been used medicinally for centuries. It contains salicylic acid; aspirin is a synthetic derivative of this compound.Other willow species are the host, both larval and adult, for moths and butterflies.