The tree house was designed to blend in with its natural surroundings. Cedar tongue-and-groove boards, cedar shingles and hand-split oak shakes make up its exterior cladding. The combination of these neutral colors is not only very attractive but is also effective in breaking up the outline of the structure, making the tree house less oppressive in its surroundings.More:9 Incredible Tree Houses5 Fantastic Homes With a Tree House FeelPennsylvania Hobbit House