This adds three plus the margin of success DR (minimum 4, maximum 13) to the target as thick bark covering their body.

Affliction [29] 
    Advantage [+60%] 
        DR 3 [6] 
            Semi-Ablative [-20%] 
            Can't Wear Armor [-40%] 
    Advantage (Margin-Based) [+60%] 
        DR 1 [2] 
            Semi-Ablative [-20%] 
            Can't Wear Armor [-40%] 
    Malediction (As Regular Spell) [+100%] 
    Based on Activation Roll [+5%] 
    Magical [-10%] 
    Spell Components [-30%] 
        Must say "bark" in Latin 
        Must gesture with hands 
        Must hold a handful of oak bark 
Levels 2-5 [35/41/47/53] 
    Add 3 to base DR [+60%]