Another interesting destination in Vancouver is the Capilano Suspension Bridge Park. Attaching tree houses successfully to trees is an age old endeavor fraught with challenges. This park is visited by hundreds of thousands of guests every year and these tree houses are constructed without driving any fasteners into the Douglas-fir trees! If one reviews the myriad number of tree house books that exist out there one can appreciate how this is no small feat. It is accomplished with a series of well placed adjustable girdles that also serve as attachment points for the suspension bridges.
There is also a really long suspension bridge across a river and a gravity defying cliff walk similar to the new one at the grand canyon. Based on the photos I've seen of the one at the grand canyon, one might argue this cliff walk is better. If you find yourself in North Vancouver, check it out.