I know your frustration...one of the small tracts that I hunt has an understory composed of mostly multiflora rosa and hawthorn (or is hackberry?) trees (the ones with big 6-8 thorns shooting out of the trunks). We bulldozed trails through there about 5 years ago and try to spray and maintain but the sh$t just keeps coming back!! It's so irritating. But, there have been some big deer in there in years past...