Since this is a va case,
The fire is of minamal concern to me. If the kids reasonably woodwise "a small bonfire" is not going to take out the woods, and if you must put it out, (and if it was my backyard I would immediatly) thats what water and fire extinguishers are for.
Approch: I would be visably armed, and have my cell phone. and annonce that kid is tresspassing (ifit was my land) and that he need to leave.
if the kid refuse I would call the cops.
Too be honest, I bet the kid would skuttle as soon as he relized the call had been made.
Now, if, when told that he was trusspassing, and that hecan't stay, he was polite, contright and apologetic, I may ask him to talk to me and offer help (call a shelter, or adult the kid trusts)
I don't see how grabbing and physically attempting to remove him is good for anybody.
To be frank, such actions are rash (and obviously) dangorous. Seems to me that homeowner was all brawn and no brain, and something of an a**hole to top it off.