Shrub or small tree to 20 m, though typically 5–7 m, trunk massive and gnarled, 0.9–1.2 m dbh. Bark thin, fibrous, reddish grey, soon flaking. Crown initially conical, later rather broad and open. Juvenile leaves 1–2 × 0.1–0.2 cm; mature leaves 2–4 mm long, acute. Male strobili 1–2 mm long. Female cones axillary, usually clustered or in whorls of four, subglobose, valvate, 2.5–3.8 cm diameter. Seed scales in a single whorl of four, reddish brown inside, dark brown outside, rough and woody with a warty external face. Seeds with three corners, extremely resinous, wing inconspicuous. Coates Palgrave 1990, Pauw & Linder 1997, Farjon 2005c. Distribution SOUTH AFRICA: Western Cape (Clanwilliam district: Cederberg mountains). Habitat Mist-cloaked mountains and cliffs, between 915 and 1980 m asl. In its natural environment it can tolerate shallow, infertile soils, and experiences regular summer droughts and winter snow and frosts. USDA Hardiness Zone 9. Conservation status Endangered. Illustration Coates Palgrave 1990; NT895. Cross-reference K324. Taxonomic note The recently suggested English name Clanwilliam Cypress is more accurate, but has to compete against the hallowed vernacular Cedar – from which the whole Cederberg range takes its name.
Clanwilliam Cedars are the subject of intensive investigation by South African botanists, foresters and conservationists (Manders et al. 1990, Mustart 1993). Pollen analysis and historical records suggest that the species’ range was significantly larger in the past, but the main stands of it were ruthlessly exploited for their timber by European settlers in the Cape, and few mature trees now remain. Re-establishment is proving to be very slow and difficult, even with heavy input of finances and management. Plants face various threats, including seed predation by birds and rodents, grazing of seedlings, low seed yields and illegal timber extraction; fire, however, remains the chief concern. Due to their high resin content cedars burn incredibly fast, and can even explode! Yet fire is essential for seed release and seedling establishment. Rigorous management of the Cederberg area, with routine, controlled burning, may be the only way to save Widdringtonia cedarbergensis, and attempts are ongoing (see, for example, Plantzafrica 2003, Global Trees Campaign 2008). It is recommended for cultivation in South Africa, though not for planting too near a braai (barbecue) area … It is also used as a Christmas tree there (Plantzafrica 2003).
It is not surprising that such an interesting tree should attract the attention of horticulturists, and young plants appear occasionally in British gardens. There is a shapely individual of 1.2 m (2008) in Christine Battle’s arboretum at Upton Cheyney in Gloucestershire, for example, planted in 2006. No old specimens are known, however, and Johnson (2007) notes that a bush growing at Pine Lodge gardens in Cornwall is unlikely to make a tree. It is established in California: for example, in the botanic gardens around San Francisco.