Sorbus aucuparia (Rowan), is a tree native to most of Europe except for the far south, and northern Asia. In the south of its range in the Mediterranean region it is confined to high altitudes in mountains.
Rowans is unrelated to the true Ash tree though the leaves are superficially similar.
It is a small to medium-sized deciduous tree typically growing to 8–10 m tall, more rarely 20 m, and exceptionally to 28 m. The bark is smooth, silvery grey of young trees, becoming scaly pale grey-brown and occasionally fissured on old trees.
The shoots are green and variably hairy at first, becoming grey-brown and hairless; the buds are conspicuous, purple-brown, and often densely hairy. The leaves are pinnate, 10–22 cm long and 6-12 cm broad, with 9–19 (most often 13–15) leaflets; each leaflet is 3–7 cm long and 15–23 mm broad, with a coarsely serrated margin; they are variably hairy, particularly the petiole and leaf veins on the underside.
The hermaphrodite flowers are produced in large terminal corymbs 8–15 cm diameter with up to 250 flowers, the individual flowers 1 cm diameter, with five creamy-white petals, and are insect pollinated. The fruit is a small pome 6–9 mm (rarely up to 14 mm) diameter, green at first, ripening bright red in late summer, and containing up to eight (most commonly two) small seeds.
Rowan is very tolerant of cold and is often found at high altitude on mountains, hence it's other name the Mountain Ash; in the UK it occurs at up to 1,000 m altitude, higher than any other tree, and in France up to 2,000 m.
It is very tolerant of a wide range of soil conditions, including thin acid soils and cracks in cliffs. It also fairly frequently grows as an epiphyte in clefts or cavities of larger trees such as Scots Pines, though epiphytic specimens rarely have growing conditions adequate for them to reach maturity.
The fruit is an important food resource for many birds, notably Redwings, Fieldfares, Blackbirds, Mistle Thrushes and Waxwings, which in turn disperse the seeds in their droppings.
The foliage and bark is eaten by Red Deer, Roe Deer, and Mountain Hares, and a small number of insect larvae.
The berries, when ripe can be mixed with sugar and boiled down to a jelly though some crab apples can be neccesary for pectin to help it to set.