Huldras

The Huldra, Thomas Dodd. Available for sale at Redbubble.

The myth is that you follow the Huldra into the forest. Then once the beautiful and enticing Huldra turns away from you, you see that her back is like an oak tree with a hollow spot and that she has an animal's tail.

These are the more chaste images of her I could find--I leave it to you to make your own Google search. There is certainly a dearth of huldra representation. In terms of tree women, Daphne definitely gets more artistic attention.

Huldra by Maria Friberg Berntsson. Here.

Huldra [with red-hatted gnomes!]