Crownshaft

An elongated circumferential leaf base formation present on some species of palm is called a crownshaft.

The leaf bases of some pinnate leaved palms (most notable being Roystonea regia or the royal palm but also including the genera Areca, Wodyetia and Pinanga) form a sheath at the top of the trunk surrounding the bud where all the subsequent leaves are formed.

Each layer of the crownshaft is a distinct leaf base and is usually made of a tough fibrous material with a feel similar to leather and in many parts of the world, it is cured and used to prepare covers, sheets and roofing material.

In time the old leaf separates at the base and falls away leaving the distinct rings and ridges of the leafbase scars seen on the trunks of many species of palm.

Juveniles and younger palms usually grow faster than adults; this is demonstrated by the larger gaps between scars at the base as compared to the top.