Since the mid-1990s, recreational tree houses have enjoyed a rise in popularity. They are built among the branches, around or next to the trunk of one or more mature trees, and are raised above the ground. Tree houses can be used for recreation, work space, habitation or as temporary retreats.
Wood is commonly used for structural parts and cladding due to its strength, light weight and low cost. Steel is used for brackets, cables and bolts, including specialized tree bolts capable of supporting up to 6,000 pounds.