The Askafroa (Swedish: wife of the ash tree) also known as the Danish Askefrue and German Eschenfrau, is a type of legendary creature in Scandinavian and German folklore, similar to the Greek Hamadryads. The Askafroa is the guardian (tutelary deity) of the ash tree. The Askafroa was thought to be a malicious creature that did much damage, and to appease her, it was necessary to make a sacrifice to her on Ash Wednesday.
The Swedish scholar Hyltén-Cavallius recorded in his ethnographic work Wärend och Wirdarne a belief of a female creature living in the ash tree, in Ljunit Hundred. The elders sacrificed to the Askafroa on the morning of Ash Wednesday. Before the sun had risen, they poured water over the roots of the ash tree. While doing this, they said: "Nu offrar jag, så gör du oss ingen skada", meaning "Now I sacrifice [to you], so that you do us no harm". Hyltén-Cavallius further writes that they believed that if anyone broke branches or twigs from the ash tree, they would become ill.