You touch a willing creature. Until the spell ends, the target's skin has a rough, bark-like appearance, and the target's AC can't be less than 16, regardless of what kind of armor it is wearing.
Material Component:
a handful of oak bark
Verbal Component:
Corpus Armatus di Sylvaticus
Verbal Component (Alternative):
With natures blessing from tree-kin, I armour my body with barkskin.