Tree houses or tree forts, are platforms or buildings constructed around, next to or among the trunk or branches of one or more mature trees while above ground level. Tree houses can be used for recreation, work space, habitation, observation or as temporary retreats.
 
Many areas of the world have no specific planning laws for tree houses, so the legal issues can be confusing to both the builder and the local planning departments. Treehouses can be exempt, partially regulated or fully regulated depending on the locale.
 
In some cases tree houses are given exemption from normal building regulations, as they are not considered to be a building in the normal sense of the word. An exemption may be given to a builder if the treehouse is in a remote or non-urban location. Alternatively, a tree house may be included in the same category as structures such as garden sheds, sometimes called a "temporary structure". There may be restrictions on height, distance from boundary and privacy for nearby properties. There are various grey areas in these laws, as they were not specifically designed for tree-borne structures. A very small number of planning departments have specific regulations for tree houses, which set out clearly what may be built and where.