im not sure that this is the right forum for this question but here goes. im clearing all the junk trees out of about a 5 acre walnut patch. mostly hedge and thorny locust. the grove is fairly mature already with severall trees around 25 inches. the majority of the trees right now are about 15 inches. now my question. my stepdad is wanting to take a 953 cat or D8 and push out the stumps from the trees that i cut out. he will be within 5 feet of the walnuts making ruts and the whole 9 yards. i told him he was crazy and that he would kill all the trees that i was just protecting. so im hoping that i can show him this and he will see that its not a good idea. whats the minumum distance that you can drive a 50 000lb machine from a tree and not do any damage to the root system? thanks.