Sometimes its easy to forget how out of touch we are with the environment. I'm sure this is exactly what these architects had in mind when these were designed and built.

As the tree continues to age wont you end up with pretty serious structural stability issues?

Reminds of this series called the pendragon series. Part 5 (I think) shows a race of cats living in trees on the planet/territory called Eelong

Reminds me of a dream I had a couple years ago. Instead of trees, we all lived in giant mushroom houses of varying height. Some would kind of grow into each other forming an organic city "block." (the smurfs) These are neat, too.