What can I spray in the woods to control unwanted growth but not harm trees?

[Fishinspot1]

The Lane shark I have is the LS3 which is for the mid size tractor. Mine is a Kubota L3300. Cost was about $6k including the third function kit I installed. Absolutely the best attachment I have bought for my property. I can leisurely drive the roads/trails and keep it cut back easily. It’s actually enjoyable.