Some characters live in trees. Not in a tree house, but actually inside a hollow tree trunk. Usually there will be a doorway in one side of the trunk, and a substantial space inside. More elaborate arboreal abodes may have front steps, windows, back doors, and even chimneys visible from the outside. The nicest ones have several fully-furnished rooms inside. This usually leads to a lot of Fridge Logic if one starts to seriously think about it. How is the tree alive and green if it's been hollowed out? (While dead trees are an option, they are usually shown as green and vibrant.) How can you fit an entire two-bedroom apartment on the inside of a tree? How are there windows in the upper leaves that should logically only have the thin ends of branches behind them? Don't expect any of these questions to be answered. The use of this trope often shows that the characters are woodsy or in a nature-based setting. For the trope to be in effect the tree actually has to be converted in some manner to serve as a house. A squirrel living in a hole in a tree doesn't count because that's just what squirrels do. See also Tree Top Town
- The Keebler elves (mascot of Keebler, an American cookie and cracker maker) live inside a tree, which is used as part of the company logo.
- The Wolfriders in ElfQuest live in a "Father Tree" that's subdivided into several homes. Fully justified because their tree-shapers can keep a tree alive and well while sculpting it into the required shape.
- Home Tree in Avatar: the tree is honeycombed with natural spaces where the Na'vi live.
- In My Side of the Mountain Sam makes his home in a tree. Probably one of the more realistic examples you're likely to find.
- The Berenstain Bears live in a beautifully furnished tree.
- Alan Dean Foster's Spellsinger series. The turtle wizard Clothahump's home is inside a massive oak tree.
- Terry Pratchett's The Colour of Magic has the useless wizard Rincewind captured by classical Graecian tree-spirits, the Dryads. They have resolved the "we live in a tree but the tree is still green and flourishes, indeed we and the tree need each other to thrive" paradox by being multi-dimensional - indeed their Tree shares many attributes of a Tardis, by being far larger on the inside than on the outside. The Tree of the Dryads and the great forest tree they seemingly inhabit may not occupy EXACTLY the same dimension of space-time...
- Larry Niven's The Integral Trees had an example of this In Space: a neutron star orbited by a ring-shaped cloud of breathable gas, where huge, multi-kilometer-long "integral trees" orbited within and provided shelter, nourishment, and raw materials for humans who colonized the system.
- In Mister Rogers' Neighborhood of Make Believe, X the Owl lived behind a door on the trunk of a tree. (Henrietta Pussycat lived in the same tree, but in a small house attached to a branch, so that doesn't count.)
- Dungeons & Dragons, Dragon magazine #73 module "Forest of Doom". The Drow have hollowed out part of a gigantic tree and built a fortress inside of it.
- At least in early editions, dryads live inside hollowed-out trees.
- Ariel, from Shakespeare's "The Tempest," is found by the sorceror Prospero inside a tree, though whether the spirit lives there or is merely caught is sometimes debated.
- Link lives in an arboreal abode in both Ocarina of Time and Twilight Princess.
- SNES RPG Sailor Moon: Another Story has the Sailor Senshi splitting up and going around the world. Sailor Jupiter visits the exotic, mysterious land of Canada where people live inside trees.
- Quite a lot of the Minish in The Legend of Zelda: The Minish Cap live in trees.
- The residents of Fortree City in Pokémon Ruby and Sapphire.
- The citizens of Cleyra in Final Fantasy IX live in a giant tree that is protected by a sandstorm.
- Telvanni wizards from Morrowind live in humongous tree-like fungi.
- Fairly common in Kevin & Kell: The title characters and the recently married Lindesfarne and Fenton have residences in large hollowed-out trees.
- In My Little Pony: Friendship Is Magic Twilight Sparkle lives in a tree which has room not only for living quarters, but for an entire library.
- Many of the characters in Winnie-the-Pooh, Piglet and Pooh himself most notably.
- Bugs Bunny lives in a tree in at least one cartoon, "The Case of the Missing Hare".
- Parodied on The Simpsons. In "Saddlesore Galactica", horse racing jockeys are revealed to actually be subterranean elf-like creatures who live in "a fibreglass tree".
- Finn and Jake from Adventure Time live in one.
- Chip and Dale lived in a furnished base in Chip 'n Dale Rescue Rangers.
- The Kids Next Door have their Home Base in a tree; they all have regular houses to go back to but they spend all day there anyway.
- In the film Once Upon a Forest Cornelius lives in a tree, with windows and doors carved into it, and a library on the inside. Lucky thing the humans never notice it later in the film.
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