Build House on Tree Top?

Yes, they can last a long time. There are also some spherical dwellings suspended in trees. I suspect Googling "tree house" could turn up many intriguing examples.

Trees that have died will have root deterioration and lose structural stability. Depending on the type of wood, and environmental conditions, it can deteriorate quickly or last forever. Also, the groundwater levels could play a role.

http://forestpathology.cfans.umn.edu/pdf/Blanchetteabc.pdf

This one looks like it will be around for awhile. However, make sure you have a termite bond.

Why build a treehouse using dead tress, what with all the uncertainties involved, such as insect and mold/fungus infestations, not to mention the other problems others above have pointed out?

I'm a big fan of the TV program "Treehouse Masters", and they only use LIVE trees to build a new treehouse in. My recommendation from you, from a structural engineer's standpoint, is NOT to build with dead trees. If you have already have done so, then you'll have to deal with the consequences when TSHTF......

It's virtually impossible for us here to ascertain the longevity of dead trees, as there are so many factors involved, and for the fact we would need to perform a field inspection of the trees to determine the conditions.

Live tree will grow and cause building movement?

When designing and building a treehouse with live trees, the future growth (or girth) is taken in account.

Tree movement will be most likely much less for a live tree vs. a dead tree. Think of a green branch vs. a dry dead branch and how each bends and snaps (if at all for the green one).

Even a live tree can have a rotted core. So why take a chance on dead ones?

How long they can stand for takes in a lot of factors. Like the type of tree, how soft the ground is, how wet it is, how mature the tree was, ect

Maybe this will aid you.

http://www.animalplanet.com/tv-shows/treehouse-masters

they can last a very long time, it is not to worry about