Q: We have a watershed area in our yard that I want to dig out and put in a dry steam bed to control the flow of water during storms. The problem is that there are some tree roots where I want to put the stream. The roots are two inches in diameter. Would cutting them hurt the trees?

A: I have a large, but declining, sweetgum in my landscape whose large roots were cut to install a dry creek bed five years ago. I have no doubt that the root damage weakened the tree. This is a case where you need the eyes of a certified arborist to evaluate the situation and advise you. If you severely hurt the tree, its removal will be much more costly than hiring a consultant. Get one at www.georgiaarborist.org.