The Swiss Family Treehouse, based on the Disney film Swiss Family Robinson and open to the public November 1962, was an Adventureland staple for more than thirty years. In 1999, it was replaced by Tarzan's Treehouse, based on another Disney film, the name of which has been long forgotten.
The decision to change the tree house's theme was based on three factors. First, as the turn of a new century approached, pretty much nobody remembered Swiss Family Robinson, and those who did just remembered the part where the family had a big race involving lots of different animals. Sure, the tree house was cute, but the monkey riding the ostrich (or whatever it was) was far more memorable.
Second, gardeners had allowed a seed from the tree to grow unchecked, and there was now a second large tree next to the first one -- right in the middle of Adventureland's main walkway, in fact. Nobody wanted to cut down this fine tree, so Imagineers looked for a way to incorporate it into a new attraction.
Third, the Robinson's were way behind in their rent.
The main differences between Tarzan's Treehouse and the Swiss Family Treehouse are summarized in the table below.
Swiss Family Treehouse
Appeared two years after Swiss Family Robinson was in theaters
Appeared mere seconds after Tarzan hit theaters
Entered and exited via stairs up the main tree
Entered end exited from separate trees. Trees connected by a suspension bridge
Has a funny bit where baby Tarzan cries in the Tarzan yell
No animals visible
Delightfully showcases the giant jungle cat that ate Tarzan's parents
Appears just as it would if the Swiss Family had stepped out for a moment
Appears just as it would if Tarzan's treehouse were a Disneyland attraction
Features actual props from the film and Captain Nemo's organ from 20,000 Leagues Under the Sea
Features actual props from the film
Tastes like cement
Tastes like cement
Contains no fiberglass Tarzans
Contains multiple fiberglass Tarzans
Has garbage dropped by visiting guests beneath it
Has an interactive play area beneath it
Was the inspiration for the title of the book Vinyl Leaves
Was the inspiration for the title of the book Bart Simpson's Treehouse of Horror
Trivia: When the late Edgar Rice Burroughs was brought to Disneyland, he had no comment on this attraction (or any other attraction, for that matter).