Tree Hugger

Tree Hugger shares the caster's armor class with the target tree. The caster touches the tree and recites the spell, causing his armor class to be added to the natural armor class of the target tree. The spell lasts for a number of hours equal to half the caster's spell level (round down, minimum 1 hour) plus the caster's spellcasting modifier. The caster must continually be touching the tree for the spell to last. Should the caster become separated from the target tree, the spell immediately ends.