takes double damage dice when on fire

Base Ac is 16

You feel the earth with your body to detect movement through its medium. Until the beginning of your next turn, you have tremorsense to a range of 30 feet in all directions from the point the spell was cast.
You can sense which direction objects or creatures are moving, and what general size category objects or creatures may be. You cannot tell the difference between creatures and objects using this sense, nor can you tell what kind of creature or object it is.
Every foot of fluid or loose material, such as water or sand, counts as two feet for the purposes of considering maximum distance with this tremorsense

When in close proximity with the same species of Ent the radius of Tremor sense increases by 10 feet

increases ability score