String tree

A small metal guide, usually holding one or two strings, fitted to a headstock to increase the angle at which they leave the nut.

The problem it solves appears when a tuner post sits lower than the nut slot, so the string leaves the slot at a shallow angle, rattling in the slot and losing tuning stability. Pressing the string down with a guide restores the angle, and the guide also acts as a witness point at a fixed position. The trade is extra friction where the string slides, which is why lubricating the contact helps on tremolo guitars.

Example: two strings on a flat, six-in-line headstock usually need trees, while the other four have enough natural break angle without them.

String tree

See also