Native American tribes of the Northeast used willow trees for many things: tools, furniture, baskets, dyes, and even as a fever reducer. The bark contains salicin (a chemical precursor to aspirin), and many civilizations across the globe consumed it as an anti-inflammatory.
Willow saplings were also used for fishing weirs — essentially, permanent fish traps. In fact, ancient fishing weirs (dating back about 5,000 years) have been discovered under Boston's soil several times (e.g., during excavations for Boston's Green Line, and during the construction of the John Hancock Tower) — which suggests that they were built and maintained by ancestors of the Massachusett tribe.
There are four willow species included in one of Harvard's most unusual exhibits: the Glass Flowers.