Trees grow in many shapes, and can be trained into many more, so it's not surprising that people have made use of these over time. Any piece of timber where the grain follows the form will be at its strongest. The three legged table shown here is an example of the rustic 'bush' furniture created by the first British settlers in Australia.
Rugged chairs such as this one, using either a single 'knee' halved, or a pair of similar shape, are of a type made in Scotland. Items of wet clothing could be hung over the rails to dry in front of the fire.
The Irish 'hedge carpenter' was a recognised craftsman, able to create a variety of useful wooden items. He was so called for his ability to find many of the shapes he needed for his products - be they tools, farm implements, or furniture - growing naturally. This simple wooden seated chair with splayed legs has used a single naturally grown angle, halved and spliced together, to form its back bow.
This elaborate 'gothic' chair was grown by John Krubsack in USA. In 1908 he transplanted 28 Box Elder saplings he had grown from seed, training and grafting them together as they grew. In order to achieve thicker legs, he allowed these an extra year of growth, finally harvesting the finished chair after 11 years.