This is a somewhat joke-y subclass that represents a very militant eco-activist. It's a bit tongue in cheek, but still fits the fantasy of someone sworn to protect nature.
Level 3
Aura of Thorns.
Gain an aura with a reach of 1. If an ally within the aura is attacked (not hit) while you have judgement dice, you can expend them to deal that much damage to the attacker. If you don’t, roll your judgement dice.
Furry Friends.
You gain advantage on Influence with animals and can communicate simple ideas with them through body language and primal sounds.
Level 7
Meat is Murder.
(1/encounter) If an ally or animal within range gains a wound or is otherwise injured, move up to twice your speed and make a free melee attack against the attacker. On hit, they take twice your judgement dice additional damage, whether you have judgement dice available or not.
Level 11
Side-Eye.
(1/turn) If an ally (not you) within your aura of thorns is attacked, you can impose disadvantage on the attack.
Level 15
Mess with the Bull - Get the Thorns.
(1/safe rest) For 1 minute, your body becomes half-animal, half-tree: +2 speed, +WIL damage, and enemies in melee take WIL d6 thorn damage when hitting you.