The Wood Woad is a mortal who gives his life to become a guardian of the forests whose heart is changed into that of a plant.  You have found a way to emulate the noble Wood Woad.

Wooden Fist

At 3rd level : You can change your hands into wood and back again at will.  This allows you to do either bludgeoning damage or piercing damage with your unarmed strike.  In addition to this, your hands count as both an armed and unarmed weapon. 

Thorn Whip

At 3rd level : You can the ability to cast Thorn Whip as a cantrip at will, using your wisdom as your spellcasting modifier.

Thorn Shooter

At 3rd level : You can replace an unarmed attack with a thorn grown and shot from your arm.  This has a range of 60’ at 3rd level, 90’ at 6th level and 120’ at 9th level.  This is a ranged attack that uses your wisdom modifier for attack and damage rolls.  It has a base damage equal to your martial arts roll.

Wooden Skin

At 3rd level : While unarmored and not wielding a shield, your skin hardens into wood.  This counts as natural armor, and is added to your unarmored AC.  This bonus is equal to your Wisdom modifier.

Sustained By Nature

At 6th level : Nature itself sustains you.  As long as you have air, earth, water and sunlight, your body creates its own sustenance.  You no longer need to eat food.  If you are underground (or missing one of the other ingredients) for more than a number of days equal to your wisdom modifier, then you begin to starve unless you eat as normal.

Photosynthesis

At 11th level : At the start of your turn, if you have less than 1/2 you maximum hit points, and your feet are planted on the earth, you regain hit points equal to your wisdom modifier.

Nature’s Avatar

At 17th level : As an action, for 1 minute you gain the full power of the Wood Woad.  Your natural armor increases by your wisdom modifier (this stacks with your wooden Skin).  In addition, your photosynthesis increases to 10 points a round (no matter what your starting hit points are).  Once you have used this ability you need to take a long rest before you use it again.  You can expend 2 ki points to activate this ability an additional time per long rest.