Currently evil map sections have too much in the sense that once a player is established behind walls/traps, they can use the endless recovering zombies for training their soldiers very quickly thus the gameplay difficulty decreases immensely by having super soldiers. So while it might be difficult at first it's not properly balanced to provide longterm difficulty.
Suggested Improvements: The frequency of undead reanimation should arrive less often, but as an entire map effect. So instead of 55 body parts reanimating individually with a high frequency, the 55 body parts would reanimate all at the same time yet less often. This would decrease the rate at which soldiers can gain experience from the undead reanimation as well as provide a more effective longterm difficulty.
*In regards to the original topic:
Deadly Shrubs/Plants A few shrubs/plants have a small percent chance of generating some random effect on the dwarf walking on top of them. The random effects can include: Sleepy, Hungry, Dazed, Happy Thought, UnHappy Thought, Slowed, Scared, etc., etc., etc., .
Deadly Trees A few trees are immobile sleeping monsters which cannot be targeted for attack until they are awoken. The immobile sleeping monsters will only awaken when someone trys cutting them down. They have a wooden maul attack, 2 wooden mace attacks and can throw many wooden arrows for a ranged attack. A very small percentage of these can actually move once awake.