Ulmus bergmanniana

Ulmus bergmanniana, commonly known as Bergmann's elm, is a deciduous tree found across much of China in forests at elevations of 1500–3000 m.

Description

The tree is very closely related to the wych elm Ulmus glabra; it can reach a height of 26 metres (85 ft) with a wide-spreading crown, and a trunk of about 0.9 m d.b.h. The bark is longitudinally fissured, and varies in colour from greyish-white to dark grey. The pubescent leaves range from obovate to elliptic, less than 16 cm (6.3 in) long, and bluish-green in colour. The perfect, wind-pollinated apetalous flowers are produced on second-year shoots in February, followed by generally orbicular samarae less than 16 mm in diameter. Branchlets do not possess the corky wings characteristic of many other elm species.

Pests and diseases

U. bergmanniana has a moderate resistance to Dutch elm disease; in trials in Oklahoma it was also found to be eschewed by the elm leaf beetle Xanthogaleruca luteola , but further north at the Morton Arboretum was moderately to highly preferred by the insect. The species is also susceptible to the elm leafminer.