Seljefløyte (willow flute)
A wooden pin or fipple set into the end of the flute guides the air flow through a channel to a sharp edge, where the tone is created. The seljefløyte has no finger holes; the pitch is regulated by overblowing and by using the index finger to open, half close or close the hole at the far end. The seljefløyte was originally fashioned from a willow branch cut in early spring during the time when the sap rises and the bark loosens from the wood, forming a hollow tube. The instrument could only be played for a few weeks before it would dry up and become unusable. Today the flutes are made from plastic, wood, or metal so that they can be enjoyed year-round.
The seljefløyte produces tones in the overtone series, which has been called the "natural" scale. The composer and folk musician Eivind Groven has written extensively about this scale and its relationship with Norwegian traditional music. The seljefløyte was traditionally used as a herder's instrument. Today it is used to play both traditional tunes and folk song melodies.