Tree 25–35 m tall in habitat, habit pyramidal or fastigiate when young, later spreading. Bark thick, rugged, greyish, with corky fissures. Young twigs covered in whitish tomentum, later glabrous with salient lenticels, stipules persistent. Leaves tardily deciduous, oblong, oval, or lanceolate, 6–12 cm long × 4–8 cm wide, base rounded or heart-shaped, apex slightly attenuated; leaf margin edged with 4–12 pairs of triangular teeth ending in short mucros, separated by rounded sinuses; leaves emerge covered in whitish silky tomentum, upper surface dark green and sparsely hairy or smooth when mature, underside clothed in dense, short, whitish tomentum; 9–15 pairs of veins, salient beneath, extending to tooth tips without ramification, no intercalary veins, petiole pubescent, 0.5–1 cm long. Cupule almost hemispherical, 1.5–2 cm long × 1.8–3 cm wide, covering about one third of the nut, scales elongated, spreading, straight, or recurved according to their position, 0.6–0.9 cm long, covered in white tomentum, inside of cup silky. Acorns oblong, ovoid or nearly cylindrical, brownish, lightly striated, 3.5–4.5 cm long × 1.7–2.8 cm wide, slightly swollen at base and tapered at the tip, peduncle short (up to 1 cm); acorns usually in pairs and often in more numerous groups, maturing in the second year. (le Hardÿ de Beaulieu & Lamant 2010).
Distribution Algeria Kabylie Mountains Tunisia Krumerie Mountains (one population)
Habitat Endemic to the coastal mountainous regions of northern Algeria and Tunisia, from 200 m to 1200–1600 m asl, in association with Q. suber, Q. canariensis, and Abies numidica.
USDA Hardiness Zone 6
RHS Hardiness Rating H7
Conservation status Vulnerable (VU)
This species is so closely allied to Q. castaneifolia that some botanists have not recognised it even as a variety. Chiefly it differs in its flowers and fruits, notably in the female flowers having four or five slender spreading styles (only three, shorter and more erect, in Q. castaneifolia); in the shallower acorn-cup with longer, more slender scales; and in the more clustered and often more numerous fruits. The young shoots are more densely downy, the leaves are smaller and the bark is more deeply furrowed (Bean 1976). Bean states there is no reliable difference in the leaves, but according to le Hardÿ de Beaulieu & Lamant (2010) they are shorter and proportionally wider in Q. afares, and the teeth tend to be more rounded. Young twigs are more densely downy and bark more deeply furrowed with coloured, corky fissures.
Quercus afares is sympatric with Q. suber and Q. canariensis over most of its distribution in North Africa. Although these two species are phylogenetically distant (the former in subgenus Cerris, the latter in subgenus Quercus), Mir et al. (2006) considered Q. afares to be a stabilised hybrid that had originated from hybridization between them. Simeone et al. (2018), however, found no evidence of this.
It is rare in cultivation and less vigorous than Q. castaneifolia. Two trees were grown at Kew from seed sent from Algeria in 1869, of which one does not survive but reached 20 m × 71 cm dbh in 1951; its companion was still slightly smaller in 2010, measuring 20 m × 70 cm dbh. The leaves of these trees are smaller than in Q. castaneifolia, the largest being 5–13 cm by 4.5 cm (Bean 1976; Tree Register 2020). Three trees are recorded at the Sir Harold Hillier Gardens, the two larger of which were 18.5 m × 42 cm and 16.7 m × 33 cm in 2010 (Royal Botanic Garden Edinburgh 1997). It is more common in France where there are large trees in several collections such as at the Arboretum national des Barres, where it often fruits freely though it has suffered some frost damage during particularly bitter winters (le Hardÿ de Beaulieu & Lamant 2010); a notable specimen is found at the Arboretum Gaston Allard in Algiers (pers. obs. 2012). An additional introduction was made in 2008 when seed was sent from Algeria to Beatrice Chassé at Arboretum des Pouyouleix, France, and distributed to several collections, including White House Farm, England, where it had reached 5 m in 2019 (M. Foster, pers. comm.). Some plants in cultivation appear to be hybrids with Q. cerris, presumably raised from garden seed.
In New Zealand this species seems to be remarkably popular, based on its availability in nurseries (e.g. Southern Woods Nursery Ltd. 2020; Greenleaf Nurseries 2020; Leafland Wholesale Tree Nursery 2020), presumably grown from seed sourced from trees at Eastwoodhill Arboretum. It is likely the seedlings are hybrids, probably with Q. cerris, and many of the more recent accessions at Eastwoodhill, of garden source, are recorded as such (Eastwoodhill Arboretum, pers. comm.). An apparent hybrid with Q. × crenata ‘Ambrozyana’ was raised at Hackfalls from seed of Q. afares at Eastwoodhill. It was 13 m × 63 cm dbh in 2004 (Berry 2016).
The epithet is dervied from the vernacular name in Arabic: الأفراس (alafras). Pomel referred to this species as chêne Afarès when he described it in 1875.