Plant Camouflage. The elemental has advantage on Dexterity (Stealth) checks it makes in any terrain with ample obscuring vegetation.
Regeneration. The elemental regains 10 hit points at the start of its turn if it is in contact with the ground. If the elemental takes fire damage, this trait doesn't function at the start of the elemental's next turn. The elemental dies only if it starts its turn with 0 hit points and doesn't regenerate.
Speak with Beasts and Plants. The elemental can communicate with beasts and plants as if they shared a language.
Tree Stride. Once on each of its turns, the elemental can use 10 feet of its movement to step magically into one living tree within 5 feet of it and emerge from a second living tree within 60 feet of it that it can see, appearing in an unoccupied space within 5 feet of the second tree. Both trees must be Large or bigger.