Plant 201

Sorbus domestica L. (Rosaceae)


Service tree

Two of the oldest plants in the Oxford Botanic Garden are service trees. At least one of these trees is thought to have been planted in the late 1780s by Professor John Sibthorp. Sibthorp apparently obtained seed from the only known service tree growing in the eighteenth-century Britain. The tree had been discovered in the Wyre Forest (Worcestershire) in 1678; it was destroyed by fire in 1862.

The service tree is similar in appearance to the rowan (Sorbus aucuparia) and wild service tree (Sorbus torminalis). However, in fruit the three species are readily distinguished. The service tree has large (2-3 cm diameter), russet to greenish-red, apple- or pear-shaped fruits. The true service tree has medium-sized (1-1.5 cm diameter), spherical, russet-green to brown fruits, whilst those of rowan are small (<1 cm diameter), spherical and red-orange. Service trees with their different fruit shapes are frequently given names: forma pomifera and forma pyrifera.

The service tree's natural range is southern and central Europe, especially the Balkan Peninsula, Italy and southern France. The species may be native in the UK but the Wyre Forest tree was probably introduced. In 1983 a small, service-tree population was discovered in an isolated part of South Wales; it is unlikely to be introduced. The species' native distribution is complicated by its apparent spread through cultivation.

Wherever service trees occur they are rare. This is perhaps partially because it is a light-demanding species and a poor competitor. Despite prolific flowering and fruiting, the service tree produces little viable seed, but it is effectively propagated vegetatively by root suckers.

The service tree's scarcity, low density and high degree of isolation would imply low genetic diversity within populations and high genetic differentiation among populations. However, analyses show the species' genetic characteristics are similar to those of common, widespread species.

The fresh fruit of service trees is very astringent but when bletted, like medlars, it becomes edible. The fruit is used as a medicine for intestinal complaints and to make preserves and alcoholic beverages. The hard, strong wood can be used to make machines and high-quality instruments and inlays.

The English name is derived from the Middle English serves, which comes from Old English and ultimately the Latin name for the fruit, sorbus. One of the tree's other English names, whitty pear, is apparently derived from the leaves being similar to those of rowan and the fruits' shape and stone cells.

Further reading

Hampton M and Kay QON 1995. Sorbus domestica L., new to Wales and the British Isles. Watsonia 20: 379-384.

Rich T et al. 2010. Whitebeams, rowans and service trees of Britain and Ireland. Botanical Society of the British Isles.

Rotach P 2003. EUFORGEN Technical Guidelines for genetic conservation and use for service tree (Sorbus domestica). International Plant Genetic Resources Institute.

Stephen Harris