Crownshaft
Encyclopedia
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 families Areca, Wodyetia and Pinanga) form a sheath at the top of the trunk
surrounding the bud where all the subsequent leaves are formed.
The crownshaft takes the form of a column above the main trunk and beneath the main crown of leaves and is nothing but the collection of the leaf bases of the plant, all tightly wrapped around one another. It is usually green in color but may be a different color from that of the leaves themselves, including white, blue, red, brownish or orange. 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. The leaf base of some palms are also used to extract coir
.
The oldest leaf forms the outermost layer of the crownshaft. Eventually the lowest palm frond dies back, the outer layer of the crownshaft splits, the leaf unwraps and pulls away from the trunk exposing the new crownshaft surface. 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. These scars usually fade over time and the distance between two successive scars is an approximate indicator of the speed of growth of the palm. In tropical conditions when growing conditions are good, the palm grows faster and the gap between scars is large; conversely when growing conditions are not optimum, plant growth is slow and the gaps are narrower. 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.
In some species of palm the shaft is fairly indistinct because the leaf bases are not wrapped around each other very tightly, and the shaft becomes extended and “loose.”
Some palm species do not form a shaft until past the juvenile stage.
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
is called a crownshaft.
The leaf bases of some pinnate leaved palms (most notable being Roystonea regia
Roystonea regia
Roystonea regia, commonly known as the Cuban royal palm, Florida royal palm, or simply the royal palm is a species of palm which is native to southern Florida, Mexico and parts of Central America and the northern Caribbean. It ranged into central Florida in the eighteenth century but in modern...
or the Royal Palm but also including the families Areca, Wodyetia and Pinanga) form a sheath at the top of the trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...
surrounding the bud where all the subsequent leaves are formed.
The crownshaft takes the form of a column above the main trunk and beneath the main crown of leaves and is nothing but the collection of the leaf bases of the plant, all tightly wrapped around one another. It is usually green in color but may be a different color from that of the leaves themselves, including white, blue, red, brownish or orange. 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. The leaf base of some palms are also used to extract coir
Coir
Coir is a natural fibre extracted from the husk of coconut and used in products such as floor mats, doormats, brushes, mattresses etc. Technically coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. Other uses of brown coir are in upholstery...
.
The oldest leaf forms the outermost layer of the crownshaft. Eventually the lowest palm frond dies back, the outer layer of the crownshaft splits, the leaf unwraps and pulls away from the trunk exposing the new crownshaft surface. 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. These scars usually fade over time and the distance between two successive scars is an approximate indicator of the speed of growth of the palm. In tropical conditions when growing conditions are good, the palm grows faster and the gap between scars is large; conversely when growing conditions are not optimum, plant growth is slow and the gaps are narrower. 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.
In some species of palm the shaft is fairly indistinct because the leaf bases are not wrapped around each other very tightly, and the shaft becomes extended and “loose.”
Some palm species do not form a shaft until past the juvenile stage.