The guardian of the ash tree

Edward Arthur Walton: 'The Old Ash Tree'
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The 'Askafroa' (Swedish 'wife of the ash tree'),
also known as the Danish 'Askefrue' and German 'Eschenfrau',
is a type of mythological being in Scandinavian and German folklore;
she is the guardian of the ash tree and was thought be a malicious
creature which did much damage, and to propriate her it was
necessary to make a sacrifice to her on Ash Wednesday.

The Swedish scholar Hyltén-Cavallius wrote it in 1864:
'The elders used to sacrifice 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'.
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A Hamadryad - a detail,
by John William Waterhouse 1917

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Split ash tree by Peter Barr
An old but defiant tree near Bakewell