The tree house has been central to various environmental protest communities around the world, in a technique, popularized, known as tree sitting . This method may be used in protests against proposed road building or old growth forestry operations. Tree houses are used as a method of defence from which it is difficult and costly to safely evict the protesters and begin work. Julia Butterfly Hill is a particularly well known tree sitter who occupied a Californian Redwood for 738 days, saving the tree and others in the immediate area. Her accommodation consisted of two 3m 2 (29 sq ft) platforms 60 m (200 ft) above the ground.