Unless absolutely necessary. Like, for example, if you need to escape a bear.
This is rule number one, and it's the most important one. If you're not sure what a tree is, congratulations, you're probably a city dweller. Let us enlighten you: a tree is a tall, green, leafy thing that will kill you if you're not careful.
So, be careful. Don't touch the trees. Unless you're a tree hugger. In that case, go ahead and hug it. We won't judge you.
Read Rule 2: Don't Make a Mess