The distribution of the Wild Service Tree, Sorbus torminalis (L.) Crantz, in the British Isles

The results of a survey of the Wild Service tree, Sorbus {armina/is (L.) Crantz (Rosace~),in the British Isles initiated by the Botanical Society of the British Isles and the Biological RecordS Centre in 11:114 are sUIJ1lf1arised and analysed. It is confirmed that the tree is a useful indicator of ancient woodland an" he~tows and that it shows a marked preference for two kinds of soil: those derived from clays and those derived" from harder limestones. The reasons for this are discussed as well as the occurrence of the species on other soils. It is suggested that the very low rate of reproduction from seed is mainly the result of seed predation and that the northerly limits of its range are inftuel1ced by the lower rate of seed production in places with \,Cooler, less sunnier summers. The pattern of modern records in England and Wales reflects to some extent the part the tree bas played in the life of the countryside over many centuries. It has been conserved and planted in some areas fOT its fruit.. its wood and for ornament, but in other areas it is scarcely known by local people and held in little regard. Today it is usually much commoner in the first of these areas. Areas where the Wild Service tree grows have been divided into three types: those where it is relatively abundant, those where it is scattered but widespread and those where it is rare. These often, but not always, show a correlation with the solid or drift geology. Mapping in this way also shows that there are large areas of England and Wales where conditions appear suitable but from which "the tree has not been recorded. INTRODUCllON In 1974 the B.S.B.I. and the Biological Records Centre, Monks Wood (B.R.C.), organised a national survey of the Wild Service tree, Sorbus tormina/is (L.) Crantz (Rosaceae) and in the same