A children's book, written in English, published in or by the 1960s, with no ilustrations as far as I remember, featuring elves and fairies that seemed overly aggressive and warlike to me.
A woodcutter lived in the forest with his little daughter and was devastating the ecosystem of the tiny elves by cutting down trees. The tiny fairies had a different ecosystem and didn't care about deforestation. Some of the fairies were playmates of the woodcutter's daughter.
The Prince of the elves approved a plan to kidnap the woodcutter's daughter to force him to stop cutting down their trees. The Princess of the Fairies approved a plan to rescue her.
It ended with a battle between the Elves and the Fairies. The elves were winning and almost all the fairies were wiped out when the noise of the battled awakened another group of tiny supernatural beings. Annoyed at having their sleep disturbed, these tiny supernatural beings poured down the mountain and wiped out most of the Elves.
So two whole communities of supernatural beings were almost exterminated because of being too warlike and aggressive.
Does anyone know what book that is?