American elm has the largest range of any of the six elm species growing in North America, covering the whole of the eastern parts of the continent west to the Rocky Mountains, but omitting the mountainous areas, high plateaus and the coldest conifer zone. It thrives best in moist valleys and flood meadows, but is quite happy when planted on drier soils.
The naturally very variable Japanese elm is one of the key species in the fight against Dutch elm disease (Ophiostoma ulmi), which has destroyed a large part of the elm populations of central and western Europe, as well as those of North America. Species from Asia seem to have the best resistance.
The Japanese elm can grow in the wild to 30 metres, with a broad crown, but there are also shrubby forms. The leaves are 8-12 cm, and the branches of some provenances have corky wings which make them attractive even in winter.
The strong-growing Russian elm, despite the common name, is also native to Finland though it is seldom planted and little known nowadays. In the province of Häme it is a typical species of the shores of Lake Vanajavesi, in rich forest soils achieving a diameter of over a metre, given a few centuries. In the past the leathery bark was used where tough bindings were needed, and the wood itself for wooden harness bows.
The wych elm grows naturally – though rare – in the south of Finland in small isolated groups, usually near forest streams. But it can be planted successfully as far north as Oulu. Its range makes it a European tree, stretching from the British Isles to western Russia, in the area between the Black and Caspian Seas.