A treehouse is a shelter built in, or supported in part by, a tree or multiple trees. Some hard definitions require a treehouse to be supported entirely by a living tree. Many bylaws omit the classification of a treehouse unless one or more supporting strutures, such as posts, touch the ground; in which case, it is classified as an "accessory building" and subject to taxes and regulations.
Historically, treehouses are associated with primitive tool-making cultures living in tropical areas. Reasons for this choice of shelter are: Increased security from ground based predators or attackers; increased observation and visual communication in hilly and densely vegetated areas; and, increased comfort from canopy microclimates.
Western cultures traditionally associate treehouses as a child's play structure. Cultural references frame treehouses as home to fantasy play; a place for children to escape the adult world; and, a private clubhouse easily defended from others by retracting a rope or ladder.
There is a modern movement toward building treehouses stemming from Environmental concerns and a desire to return to living in Natural settings. In this context, large scale homes are built with modern amenities and full conveniences. The style typically calls for the use of natural woods and recycled materials and alternative energy sources where possible. This approach to home building is also advantageous because: Treehouses may be built on steep, or uneven ground, typically unsuitable for the foundation of a traditional house. There is no footprint whereby the structure occupies topsoil suitable for other plant or other natural organisms. Microclimates up in trees can be used to create passive conditions that are warmer and dryer in the winter, and cooler in the summer, than buildings situated on the ground. Finally, the elevation of a treehouse makes it capable of scenic views not available from ground based homes.