Seljefløyte or Willow Flute

The willow flute, also known as sallow flute (Norwegian seljefløyte, Swedish sälgflöjt or sälgpipa, Finnish pitkähuilu or pajupilli), is a Scandinavian folk flute, or whistle, consisting of a simple tube with a transverse fipple mouthpiece and no finger holes. The mouthpiece is typically constructed by inserting a grooved plug into one end of the tube, and cutting an edged opening in the tube a short distance away from the plug.

The willow flute is a type of overtone flute. It is played by varying the force of the air blown into the mouthpiece, with the end of the tube being covered by the finger or left open. The tones produced are based on the harmonic series. Playing the instrument with the end of the tube covered produces one fundamental and its overtones, playing it with the end of the tube left open produces another fundamental and series of overtones. Willow flutes cannot be tuned to an equal tempered scale.

Modern willow flutes are typically made of plastic (PVC tubing is often used), but the original willow flutes were made from sections of bark cut from green willow branches. Willow flutes could only be made this way during the spring, and became unplayable when the bark dried out.