Habitat and Ecology
Molecular Biology and Genetics
Barcode data: Tetraclinis articulata
Statistics of barcoding coverage: Tetraclinis articulata
Public Records: 4
Specimens with Barcodes: 5
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1998Lower Risk/near threatened(Oldfield et al. 1998)
- 1997Rare(Walter and Gillett 1998)
Spain: The principle threat comes from urbanization, including the establishment of sport facilities such as golf courses. Historically, human-set fires have had the greatest impact on the populations. The most notable fire occurred in September 1992 when 55 ha were burnt affecting a significant proportion of the population (Nicolás et al. 2004). Regeneration after fire can be rapid although it is estimated to take 10-20 years for burnt areas to recover (López-Hernández et al. 1995). A serious fire in the main part of the population (e.g. Cenizas-Peña de Aguila) has the potential of eradicating up to 80% of the population. Post-fire regeneration of competing species such as Pinus halepensis is a problem until the plants of Tetraclinis reach maturity. Mining has been a cause for concern in the past. The extensive heaps of spoil have caused serious fragmentation of the population. In some parts of its range (El Sabinar), regeneration is hampered by grazing for sheep and goats. Competition from invasive species is also of concern; the most detrimental species being Pinus halepensis (Martinez 2008). Tetraclinis is frequently cultivated in southern Spain in gardens and as a plantation species. Some of these plantations are located close to the native population. It is thought that the origin of this germplasm is the North African (Morocco) population. Genetic contamination could be a problem although to date no studies have been carried out to investigate its potential impact.
Malta: Tetraclinis articulata was once much more common in Malta and the various places called Ghar-ghar, Ghar-ghur etc. point out to the existence of a wider distribution, and possibly small forests (Borg 1927). It apparently disappeared centuries to decades ago, mostly due to habitat alteration and land reclamation (Stevens and Baldacchino 2000). The main threats today include habitat modification and/or destruction (including land reclamation and the clearance of the vegetation) and human-induced disturbance, including the introduction of alien species such as Acacia saligna and Eucalyptus spp. Afforestation and reforestation programmes in its distribution range with indigenous and alien trees, which do not form part of its biotope are also important threats. Competition from invasive species such as exotic Pinus spp. and particularly the native P. halepensis are also seen as threats.
Tetraclinis (also called arar, araar or Sictus tree) is a genus of evergreen coniferous tree in the cypress family Cupressaceae, containing only one species, Tetraclinis articulata, also known as Thuja articulata, sandarac, sandarac tree or Barbary thuja, endemic to the western Mediterranean region. It is native to northwestern Africa in the Atlas Mountains of Morocco, Algeria and Tunisia, with two small outlying populations on Malta, and near Cartagena in southeast Spain. It grows at relatively low altitudes in a hot, dry subtropical Mediterranean climate.
Its closest relatives are Platycladus, Microbiota and Calocedrus, with the closest resemblance to the latter. In older texts, it was sometimes treated in Thuja or Callitris, but it is less closely related to those genera.
It is a small, slow-growing tree, to 6–15 m (rarely 20 m) tall and 0.5 m (rarely 1 m) trunk diameter, often with two or more trunks from the base. The foliage forms in open sprays with scale-like leaves 1–8 mm long and 1–1.5 mm broad; the leaves are arranged in opposite decussate pairs, with the successive pairs closely then distantly spaced, so forming apparent whorls of four. The cones are 10–15 mm long, green ripening brown in about 8 months from pollination, and have four thick scales arranged in two opposite pairs. The seeds are 5–7 mm long and 2 mm broad, with a 3–4 mm broad papery wing on each side.
It is one of only a small number of conifers able to coppice (re-grow by sprouting from stumps), an adaptation to survive wildfire and moderate levels of browsing by animals. Old trees that have sprouted repeatedly over a long period form large burls at the base, known as lupias.
Uses and symbolism
The wood, known as thuya wood or citron wood, and historically also known as thyine wood, is used for decorative woodwork, particularly wood from burls at the base of the trunk. Use of the burl wood kills the tree. The market in Morocco is unsustainable, focusing as it does on the burl, and has resulted in mass deforestation of the species. The species is also threatened by overgrazing, which can kill the coppice regrowth before it gets tall enough to be out of the reach of livestock.
The species is cultivated to be grown as an ornamental tree, valued in hot, dry climates. It is also pruned in a hedge form, for privacy and security. The plant can be trained for use as Bonsai specimens.
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Tetraclinis articulata - MHNT
- "Tetraclinis articulata". The Gymnosperm Database. Retrieved 2011-02-13.
- but it is ambiguous arabic name also given to Juniperus phoenicea
- Memidex: sandarac (wood) Retrieved 2012-05-16
- Collins: sandarac and sandarac tree Retrieved 2012-05-16
- Jacques Blondel & James Aronson: Biology and Wildlife of the Mediterranean Region, Oxford University Press 1999 Retrieved 2012-05-16
- Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4
- Rushforth, K. (1999). Trees of Britain and Europe. Collins ISBN 0-00-220013-9.
- Arc-genesis: Thuya Wood Retrieved 2012-05-16