Ulmus pumila

Ulmus pumila L., the Siberian elm, is native to Central Asia, eastern Siberia, Mongolia, Xizang (Tibet), northern China, India (northern Kashmir) and Korea. It is also known as the Asiatic elm and dwarf elm. It is the last tree species encountered in the semi-desert regions of central Asia. Introduced to the USA in 1905 by Prof. J. G. Jack,Ulmus pumila has been widely cultivated throughout the Americas, Asia and, to a lesser extent, southern Europe.

Description

The Siberian elm is usually a small to medium-sized, often bushy, tree growing to 10–20 metres (33–66 ft) tall, with a trunk up to 80 centimetres (31 in) d.b.h. The leaves are deciduous in cold areas, but semi-evergreen in warmer climates, < 7 cm long and < 3 cm broad, with an oblique base and a coarsely serrated margin, changing from dark green to yellow in autumn. The perfect, apetalous wind-pollinated flowers emerge in early spring, before the leaves; unlike most elms, U. pumila is able to self-pollinate successfully. The wind-dispersed fruit develops in a flat, oval membranous wing (samara) 1–1.5 centimetres (0.39–0.59 in) long and notched at the outer end. The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment may live to between 100 and 150 years .