[Cob] living tree question

[jimmy carlisle]

Okay, this may be way out there, I can't find anything close to it anywhere on the net, so this is a good place to ask it.  I have a area I want to build a cob home.  I also have a few very tall trees I don't want to cut and have to try and get the stumps out.  What would happen if I cut the trees about 8 ft. high, cut them even, and use them as corner posts for the roof?  Is this a very bad plan?  I thought of debarking them and puttting a coat of varnish on also.
   Are they going to keep growning after I do this?  I thought it would look good and blend in well.  
    I welcome all comments...