Question
We live in San Antonio, TX and have a very large Willow Oak tree that lost most of its foliage in the top third of the tree 3 years ago.  The lower branches had a decent, but not overly thick foliage. The trunk is approx. 4 feet in diameter and the tree is approx. 50 feet tall. It had a "girdling root" that was discovered and cut and we had a tree company start feeding it by injecting a deep root fertilizer into the ground once a year. We were informed that the sprouts all around the base of the tree were part of the root system and part of the tree's effort to try and save itself. So, we just let the sprouts go and now they are very thick and some are getting quite tall (5 feet). The tree is doing well now and clearly on the mend. The upper branches once again have foliage and the tree seems to be recovering nicely. We have also had record rainfall this year and last year we had a record drought. We would like to cut back some of this excessive growth of sprouts, but don't want to harm the tree. Another tree man has now told us that we shouldn't have let the sprouts go because they have become an "advantageous root system" and now the tree is dependent upon them rather than its old underground root system. We can't find any information on the Internet to confirm what he said and are wondering what we should do.  Our question is ... Can we safely thin these sprouts out? ... maybe over a period of 2 or 3 years to encourage the tree to go back to its underground root system? The tree is fairly close to the house and the base looks real overgrown and unmaintained.  Thank you for your help.

Answer
I have not heard the term advantageous root system. The sprout are coming from the parent tree's root system and feeding off this system. The foliage manufactures food and transports it to the roots form storage and use the next spring to bud out new leaves. The root system is all the same with just new sprouts coming up. It will not harm the root system or the parent tree if these are cut. Do not use any herbicide or wound dressing on these cuts. Cutting them will have no effect on the root system. The original root system is still the same whether you cut the sprouts or not. I would do this cutting in the fall after the leaves have fallen that way the roots will get the full benefit of the old leaves manufacturing food. I see no problem with this cutting.