best herbacide for killing braodleaf vines

[otisman]

I resently planted 800 fir trees(bare root saplings approx 6-8" tall staked and caged ) need to know how to kill the sticker bushes that will overtake them if nothing is done! What is the best herbicide for killing them and not my new tree, does such a chemical exist???

 

[TheJollyLogger]

A few questions that will help with an answer, and a pic of the situation would help.

What is the spacing of the firs?

Are the vines already established or are you worried for in the future?


How large an area are we talking about?