This chair by Dutch designer Floris Wubben was made by binding and splinting the branches of a willow tree, forcing them to grow into four legs.
A seat and backrest were then cut into the trunk and the whole thing inverted.
This chair is made of a (inverted) willow tree. The legs have been obtained by twisting and splinting its branches and letting it dry into the final shape. The seat and back were naturally kept in line with the bole’s silhouette. This project had been put in practice jointly with the artist Bauke Fokkema.
I've seen a lot of willow art from dutch designers recently, with the willow loving water side growing conditions I guess this is no surprise.