Zapping undead turning at a dead tree should turn it into a living tree, or an ent (for the occasional dead tree that is actually a dead ent). If it’s a tree blight, it could either do nothing or harm the blight, depending on whether one considers the blight to be an undead tree.

A “druid staff” artifact, which can be invoked to create a patch of grass similar in size to a stinking cloud, radius 4-5. Enemies within the grass radius become rooted to the ground, making them unable to move (but still able to fight, shoot, etc) for some time. While wielding it, you can chat with trees, which causes them to give you some food, mana, or rarely a pet (possibly an ent).

If ents exist, chopping down a tree angers any ents on the level.