Sorbus is treated here in the broad sense, including the subgenera Aria and Torminaria. However, these two subgenera are likely to be recognized at generic rank, based on flower and fruit characters, once molecular studies can consistently resolve their placement within the Pyrinae, overcoming current difficulties with interfertility, reticulate relationships, rapid radiation, and small samples[].
The taxonomy of Sorbus is complicated by apomixis, polyploidy, and hybridization among sections and genera, especially in Eurasia. Sorbus hybridizes with several other genera in the tribe Maleae, including Amelanchier (×Amelasorbus Rehder); Crataegus (×Crataegosorbus Makino); Aronia (×Sorbaronia C. K. Schneider); Cotoneaster (×Sorbocotoneaster Pojarkova); Pyrus (×Sorbopyrus C. K. Schneider), and Malus (×Tormimalus Holub [= Sorbus subg. Torminaria × Malus])[].

Common Name: Wild Service Tree

General Information

Sorbus torminalis is a deciduous tree usually growing up to 12 metres tall, occasionally reaching 25 metres. The bole can be 60 - 90cm in diameter, occasionally reaching 140cm[, , ].
The tree is harvested from the wild for local use as a food and source of materials. A very valuable timber, it is harvested commercially but only on a small scale due to lack of supplies. It is sometimes grown as an ornamental[].

Known Hazards

Although no specific information has been seen, the seed, and other parts of the plant, is likely to contain cyanogenic glycosides. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted.
In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[].
The levels of toxin can be detected by the level of bitterness:- sweet almonds, for example, contain only very low levels of it and are safe to eat in quantity, whilst bitter almonds (which are used as a flavouring in foods such as marzipan) contain much higher levels and should only be eaten in very small quantities. Great caution should be employed if the taste is moderately to very bitter[].

Botanical References

, ,

Range

Europe, from Britain and Denmark south and east to N. Africa, the Caucasus and W. Asia.

Habitat

Forests, mainly oak but also chestnut, hornbeam and Pinus nigra, from plains to 1,700 metres[]. Woods, usually on clay[], sometimes on limestone[].

Properties

Edibility Rating
Other Uses Rating
Habit	Deciduous Tree
Height	10.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Sorbus torminalis is a moderately cold-hardy tree, tolerating temperatures down to around -20°c when dormant, whilst the new growth in spring is undamaged at -5°c[]. It grows best in areas with hot summers[], having an optimum mean annual temperature between 10 - 17°c. It tolerates a minimum annual rainfall of aroundt 500mm,
while the optimum lies between 700 - 1,500mm[].
Prefers an open, sunny position, though it tolerates moderate shade (but fruits less well)[, ]. Grows best on warm-dry limestone soils, also doing well on clay or loamy soils. It can succeed in most reasonably good soils so long as they are reasonably well-drained and not too poor or acid[, , , ]. Plants can tolerate a pH range from 3.5 - 8[].
A moderately fast-growing tree, it commences fruiting when around 15 - 20 years old and usually lives for 100 - 200 years, though some trees 300 - 400 years old are known[].
Plants are susceptible to fireblight[].
Plants respond well to coppicing[].
When found in a truly wild situation this species is considered to be an indication of primary woodland[].

Edible Uses

Fruit - raw or cooked[, , , , , ]. The taste is best after a frost because it turns sweeter. The fruit can also be bletted if it is going to be eaten raw[, ]. This involves storing the fruit in a cool dry place until it is almost but not quite going rotten. At this stage the fruit has a delicious taste, somewhat like a luscious tropical fruit. Rich in vitamin C. The brown, narrowly obovoid fruit is 15 - 19mm long and 10 - 13mm in diameter[] and is borne in bunches which makes it easier to harvest[].

Medicinal

None known

Other Uses

The wood is heavy, fine grained, polishes well. A valuable hardwood, it is used for turning, wood carving and making decorative veneers. In earlier times it was also used to make screws for winepresses, billiard queue sticks, musical instruments etc[, , ].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[, ]. If you have sufficient seed it can be sown in an outdoor seedbed[, ]. Stored seed germinates better if given 2 weeks warm then 14 - 16 weeks cold stratification[], so sow it as early in the year as possible. Prick out the seedlings into individual pots when they are large enough to handle. Seedlings are very slow to put on top-growth for their first year or two[], but they are busy building up a good root system. It is best to keep them in pots in a cold frame for their first winter and then plant them out into their permanent positions in late spring.