Question
Hi Marc,
I just bought a house that has a huge carrotwood tree (over 50 feet tall with a
2+' truck width) in the backyard.   I live in San Diego.  The tree is about 6 feet
from the house, which has a concrete slab foundation.  I am worried that the
roots, which are pushing up the brick patio and wood deck around it, will
cause damage to the house foundation.  I've had several tree companies come
out and the opinions have varied as to wether the tree needs to come down or
if trimming will stunt root growth.  I hate to cut down such a beautiful unique
tree, but I don't want to risk damage to my house.  Thanks!

Answer
Hello, Kameron - Well a Carrotwood (Cupaniopsis anacardioides) tree is a very nice plant, and from what you've told me I think it is as big as it is going to get.  Therefore any potential damage is already done, and removal would not be necessary.  It is considered an invasive tree in Hawaii & Texas.

http://davesgarden.com/guides/pf/go/38319/

Trimming the head of the tree won't effect root growth, but you can trim the roots themselves.  No closer than about 3-times the diameter of the trunk - or 6 feet, in your case.  After trimming, install a root barrier device - a mechanical shield that slows root penetration into areas that you don't want them to go...This should have been done when the tree was smaller - but as my kids would say, "Oh, well".

Also, are there utility or water lines present that may not allow you to trim the roots?  You did the right thing consulting arborists.  A tree company isn't going to make as much money trimming roots as it would in total removal. But as you have discovered, when it comes to trees, there is no "magic" answer, only a symphony of opinions - and so I have added mine.  Best of luck with your decision.  ~Marc