European White Elm
This species is native to continental Europe, and is found chiefly on the alluvial soils of the great river valleys in the east. It is possible that it was once an indigenous British tree.
The white elm has no intrinsic resistance to elm disease. However, it is highly unattractive to the Scolytus beetle and is unlikely to become infected. Spanish research indicates that this is because of a compound, Alnulin, in the bark.
Specimens of 35 metres and vast girth are found, but height will often be considerably less than that. The tree tends to be monopodial when close grown in a woodland setting, but several ascending main stems may form where it is not competing for light. It is most closely related to American elm, but often has considerable resemblance to wych elm. Burrs and epicormic shoots produce a very rustic appearance. On damp ground, white elm may develop massive basal buttressing.
Unlike other elms native to Europe and most of the modern hybrids, white elm is essentially a riparian species highly suited to land which is regularly inundated or permanently wet. It will grow away from water, but not on calcareous soils. Its wood is less strong than that of other elms; storm damage is likely unless plantings are carefully situated (the powerful development of the rootstock suggests that the loss of an entire tree is improbable). However, storm breakage, in combination with the uncertainty arising from its lack of disease resistance, would seem to rule out any formal use. But as an element alongside alder and willow in a wetland context, white elm has a great deal to recommend it. It is clearly capable of forming a majestic tree with much of the character of traditional elm, and is very easily assimilated into the lowland rural landscape. Given the increasing interest in returning waterways to low-level management, and the inherent value of diversity, white elm deserves consideration for suitable sites. It does not hybridise with native elms, so there is no risk of genetic ingression.