Kids will be kids and it is part of their learning process.
It's unfortunate though when this turns into vandalism, in my local woods I have found live trees cut down and then nailed together into other live trees, tons of litter and old fire pits as well as clothes and furniture including an old 3 piece suite which was used in their camp probably once until it got soaked and started to stink.
Respect is all they need to learn a couple of hours of fun for them can leave an eyesore for years.
This is not just kids either I have seen adults doing similar, leaving beer bottles and all their rubbish after an impromtu BBQ in the middle of the woods.
I was almost stopped from going into my usual bushcrafting spot near Frant in sussex after a similar group had a BBQ on the land and caused a massive fire. There was a fire engine there for a month because the fire kept popping up all over the place due to the nature of the ground.
After this the landowner banned me from having fires until I persuaded him that I knew how to put a fire out thoroughly and would only light them in areas without pete soil.
Live each season as it passes; breathe the air, drink the drink, taste the fruit, and resign yourself to the influences of each.