Question
I have a couple of young trees (5-6 yrs old) that have branches coming up from the base of the trees.  I continue to cut these back, but want to know why this is happening and what I should do to remedy this.  I notice that both of these trees seems to spend more energy in sprouting these branches from their root ball that in growing as the other trees planted at the same time have done.

Answer
Why a tree sprouts and another does not is not really under stood. More than likely it is how the tree was planted. You can stop this sprouting with a chemical.  There are some growth hormones that will stop or slow the growth of these sprouts. One of these is called Sucker-Stopper a ready to use product. You might check with your local nursery/ garden type store for this product. Here is a link to information on Sucker- Stopper.

http://www.montereylawngarden.com/pdf/sucker_stopper_rtu02.pdf

You can just cut the sprouts off. IF you have not done so I would mulch around the tree with not more than 3 inches deep of organic mulch (pine straw is good) not piled up on the trunk. This will hold moisture and help shade out the sprouts coming from the root ball.