Rowan Several of the Asian species are widely cultivated as ornamental trees. North American native species in the subgenus "Sorbus (Sorbus)" include the American mountain-ash "Sorbus americana" and Showy mountain-ash "Sorbus decora" in the east and Sitka mountain-ash "Sorbus sitchensis" in the west. Numerous hybrids, mostly behaving as true species reproducing by apomixis, occur between rowans and whitebeams; these are variably intermediate between their parents but generally more resemble whitebeams and are usually grouped with them (q.v.). Rowans are excellent small ornamental trees for parks, gardens and wildlife areas. Several of the Chinese species, such as White-fruited rowan ("Sorbus glabrescens") are
Forests of the Iberian Peninsula form small enclaves or copses at the foot of rocky cliff edges or in the clearings of beech forests, on poor or acidic soils, accompanied by aspen ("Populus tremula") and mountain ash ("Sorbus aucuparia"). Birch may also grow in pure stands near the beech forests, in the mountainous areas on siliceous bedrock; these areas are typically of only small extent and generally quite patchy with sessile oak ("Quercus petraea") and trees of the genus "Sorbus". The silver fir ("Abies alba") is found on the cool, deep-soiled slopes of the flanks of the Pyrenees, from Navarre to Montseny, forming pure fir