Dryad

Their roots go deep...

Dryads are guardians and protectors of the woods and forests. Their spirits are bound to one tree, which is typically quite ancient. The woods around that tree are known as a Grove, and there is only ever one dryad per Grove.
Dryads look completely human, but with the characteristics of their tree, i.e. tall and strong, withered and gnarly, willowy, etc. The human form they present is always of the indigenous peoples of that land, so that Australian dryads will present as Aboriginal, etc.
They can control the trees of their Grove. While the trees cannot physically move around, the dryads can move branches, roots, and even the trunks of more flexible trees.
The only way for a dryad to die is if its tree dies, therefore the only way to kill a dryad is to kill its tree. Dryad magic also steers humans away from cutting down their tree - great magic is require to break that compulsion and attack the tree. If a dryad dies, its Grove will then also begin to wither and die. The moment that the dryad's tree dies, the dryad itself will disintegrate into a pile of leaves and flowers.
Dryads can magically travel be decorporealising into leaves and petals, and blow through the wind, then corporealise back into human form.

Additional Information

Social Structure

Dryads are social creatures, and will often gather together to dance and play. When danger threatens, or a unified response is needed, dryads will form a council and defer to the oldest, and thus wisest and most powerful, among them.

Perception and Sensory Capabilities

Dryads are intimately aware of everything that occurs within their Grove, and can even influence the animals that reside within their Grove.