Wild Service Tree
The wild service tree Sorbus torminalis (L.) Crantz. is a member of the Rosaceae family and is a relatively scarce tree in the British Isles. Roper (1993) and Rose (1999), amongst others, have confirmed that it is a useful indicator of ancient woodland and hedgerows and that it shows a marked preference for two kinds of soil: those derived from clays and those derived from harder limestones (Stace, 2010). The wild service tree produces suckers (which can be stimulated by coppicing) but only few of these develop into full-grown trees (Milner, 2010).
In England the wild service tree is on the edge of its European range: its northern limit is the north of England, and it ranges south to northern Africa, and from the Iberian Peninsula across to the Caspian Sea, Syria and the Lebanon.
Wild service tree is thought to be a relatively recent arrival (in geological time), to Britain, and as a rare tree it is now usually confined to pockets of lowland, ancient woodland, although it can also be found growing in hedgerows. It can often be found associated with oak and ash woods, preferring clay and lime based soils; it does not appear on wet soils. The wild service tree can be found scattered throughout Ruislip Woods and, although low in numbers, the tree appears to grow well once mature.
It is a medium-sized deciduous tree growing to 15–25 m tall, with a trunk up to 1.3 m diameter. The bark is smooth and greyish, but flaky, peeling away in squarish plates to reveal darker brown layers. The leaves are 6–14 cm long and broad with a 2.5–5 cm petiole, dark green on both sides, with five to nine acute lobes; the basal pair of lobes are spreading, the rest more forward-pointing and decreasing in size to the leaf apex, and with finely toothed margins; the undersides have small hairs when young, but both sides are smooth and shiny when older; the autumn colour is yellow to red-brown. The flowers are 10–15 mm diameter, with five white petals and 20 creamy-white stamens; they are produced in corymbs 5–12 cm diameter in late spring to early summer, and are hermaphrodite and insect pollinated. The fruit is a globose to ovoidpome 10–15 mm diameter, greenish to russet or brown, patterned with small pale lenticel spots when mature in mid to late autumn.