Cedrus

"Cedar (genus)" redirects here. For other trees with the name, see List of plants known as cedar.

Cedrus, with the common English name cedar, is a genus of coniferous trees in the plant family Pinaceae (subfamily Abietoideae). They are native to the mountains of the western Himalayas and the Mediterranean region at high altitudes. The trees grow tall with a cylindrical trunk and a wide leafy crown. The cones are erect; the leaves grow in tufts of 15–45 needle leaves, which can be bright green or blue-green with a waxy coat. When the cones are mature, they disintegrate to release the seeds, which are winged. Both pollen and seeds are wind-dispersed.

Cedar Temporal range: Albian–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Lebanon cedar in Al Shouf Cedar Nature Reserve in Barouk, Lebanon
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Gymnospermae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Pinaceae
Subfamily:	Abietoideae
Genus:	Cedrus Trew
Type species
Cedrus elegans Knight.

Cedars are often planted as ornamental trees in parks and large gardens, while others are grown as bonsai. Cedar wood and cedarwood oil are natural repellents to moths; cedar chests were commonly used by unmarried young women to store dowry items.

Etymology

The generic name Cedrus derives from Old English ceder, from the Latin word cedrus. This in turn is derived from Greek κέδρος kédros, meaning cedar or juniper.^[1] Species of both trees are native to the area where Greek language and culture originated, though as the word kédros does not seem to be derived from any of the languages of the Middle East, it has been suggested the word may originally have applied to Greek species of juniper and was later adopted for species now classified in the genus Cedrus because of their aromatic woods.^[2] The name was similarly applied to citron: the word citrus is derived from the same root.^[3] As a loan word in English, cedar had become fixed to its biblical sense of Cedrus by the time of its first recorded usage in 1000 CE.^[4]

Description

Habit

Cedars are tall resinous trees with a cylindrical trunk and a wide leafy crown. In the Mediterranean species, several main branches eventually rival the main trunk in size.^[5] The bark is smooth in young trees, splitting into scales on older trees.^[5]

Foliage

The shoots are dimorphic, made up of long thin leading shoots from terminal buds, each one accompanied by multiple short lateral shoots.^[5] The leaves are evergreen and needle-like, 8–60 millimetres (1⁄4–2+1⁄4 in) long, arranged in an open spiral phyllotaxis on long shoots and in dense spiral clusters of 15–45 together on short shoots; they vary from bright grass-green to dark green to strongly glaucous pale blue-green, depending on the thickness of the white wax layer which protects the leaves from drying out.^[6]

• 
  Foliage of deodar

Cones

Cedars are monoecious, with separate male and female cones on the same tree.^[5] The seed cones are barrel-shaped, 6–12 centimetres (2+1⁄4–4+3⁄4 in) long and 3–8 cm broad, green maturing grey-brown, and, as in Abies, disintegrate at maturity to release the winged seeds. The seeds are 10–15 mm (3⁄8–5⁄8 in) long, with a 20–30 mm wing; as in Abies, the seeds have two or three resin blisters, containing an unpleasant-tasting resin, thought to be a defence against squirrel predation. Cone maturation takes one year, with pollination in autumn and the seeds maturing at the same time a year later. The pollen cones are slender ovoid, 3–8 cm long, produced in late summer, and shed pollen in autumn.^[6][7]

• 
  Female (seed) cone of cedar of Lebanon
• 
  Male (pollen) cone of deodar, shedding pollen in the wind

Evolution

Fossil history

The oldest fossil of Cedrus is Cedrus penzhinaensis known from fossil wood found in Early Cretaceous (Albian) sediments of Kamchatka, Russia.^[8] An Early Miocene species, Cedrus anatolica, also from petrified wood and thought to be close to C. atlantica, is known from Turkey.^[9]

External phylogeny

Cedars have a similar cone structure to firs (Abies) and were traditionally thought to be most closely related to them, but molecular evidence supports a basal position in the family.^[10][11] Based on transcriptome analysis, Cedrus is sister to the rest of the Abietoideae.^[12]

Pinaceae	Abietoideae Cedreae Cedrus Pseudolariceae Pseudolarix (golden larches) Nothotsuga Tsuga (hemlocks) Abieteae Keteleeria Abies (firs) (firs and allies) Pinoideae (pines, larches, etc)

Taxonomy and internal phylogeny

Plate "CEDRUS foliis rigidis acutis perennantibus, conis subrotundis erectis" (Cedar with sharp rigid perennial leaves, subrotund erect cones) from Christoph Jacob Trew's description of the genus in his 1757 Plantae Selectae Quarum Imagines

The genus Cedrus was described by the German botanist Christoph Jacob Trew in his Plantae Selectae Quarum Imagines in 1757.^[5] The Cedrus taxa are assigned according to taxonomic opinion to between one and four species.^{[5][13][14][15]} The Cyprus cedar for example is variously considered to be a variety or subspecies of the cedar of Lebanon, or a species C. brevifolia in its own right.^[16] The deodar is sister to the Mediterranean cedars. Divergence ages are marked on the cladogram.^[15][17][18]

Cedrus	Cedrus deodara Deodar, Western Himalayas Mediterranean cedars Cedrus atlantica Atlas cedar, Atlas Mountains in Morocco and Algeria Cedrus libani var libani Lebanon cedar, mountains in Lebanon and Turkey var stenocoma Taurus cedar, Turkey var brevifolia Cyprus cedar, Troodos Mountains in Cyprus 6.5 mya 19 mya
55 mya

Distribution and ecology

Cedars are adapted to mountainous climates; in the Mediterranean, they receive winter precipitation, mainly as snow, and summer drought, while in the western Himalaya, they receive primarily summer monsoon rainfall and occasional winter snowfall.^[6] They are native to the mountains of the western Himalayas and the Mediterranean region, occurring at altitudes of 1,500–3,200 m (4,900–10,500 ft) in the Himalayas and 1,000–2,200 m (3,300–7,200 ft) in the Mediterranean.^[6] In Lebanon, a small number of cedars of Lebanon survive in protected areas including the Cedars of God near the Qadisha Valley, a World Heritage Site.^[19]

Fungal diseases of cedars include canker; collar, crown, and root rot; needle blight; Gymnosporangium rusts;^[20] and sirococcus blight, caused by Sirococcus tsugae, which kills shoots and branches.^[21] Cedar trees are robust but become vulnerable to bark beetles in drought conditions.^[20] Other pests include the giant conifer aphid, scale insects, and nematodes such as the pine wilt nematode.^[20] Caterpillars of the pine processionary moth sometimes make their nests in cedars.^[22]

Use

Cedars are popular ornamental trees and are often cultivated in temperate climates where winter temperatures do not fall below −25 °C. The Turkish cedar is slightly hardier, to −30 °C or just below. Extensive mortality of planted specimens can occur in severe winters when temperatures fall lower.^[23] Cedar wood and cedarwood oil are natural repellents to moths.^[24] Cedars are suitable for training as bonsai in varied styles.^[25] Unmarried young women used to store their dowry items in a cedar chest.^[26]

• 
  Formally planted ornamental cedars at Chiswick House
• 
  Cedar wood has a woody, slightly sweet scent, and a distinctive colour and grain.
• 
  Cedar chest by Henry Meyers, c. 1936

• 
  Large deodar in Jageshwar temple at Almora, Uttarakhand in the Himalayas
• 
  Glaucous Atlas cedar
  trained as a bonsai

See also

• List of plants known as cedar