Sometimes, when chopping down trees, an Ent can be generated. (look at the picture below for reference)

These guys are pretty hard to kill, destroy you in a couple of hits and tirelessly follow you around the map.
My questions are:
What triggers an Ent generation? Are they spawned randomly or they just stay hidden until you cut down trees near them? If the latter is true, is there a way to recognize them?
How to deal with them? Do they eventually give up on following you or you just have to turn and face them? In this case what's the best setup? (I've been thinking Logsuit+Torch, but I've never been able to test it)
Do they drop something valuable when defeated or just the usual logs+pine cones?
