I want to remove a lot of junk trees I have growing in my wooded area. Most are locust with the sharp spines ( already have had 2 flats and I only have 5 hours on the new tractor) and Osage Orange. I cut down one large Osage tree and the stump sprouted dozens of new shoots that within weeks grew 5 feet tall. I have heard of "girdling" the trunk to kill the tree. One person suggested I try covering the stump with a heavy black garbage bag to block the light from any shoots. Any suggestions?