One of the largest and fastest-growing deciduous trees in Europe. Used to be extremely common before the dutch elm disease decimated populations across Europe. The tree often exceeded 40 m in height with a trunk < 2 m d.b.h. The tree does not produce fertile seed as it is female-sterile, and natural regeneration is entirely by root suckers. English Elm was the first elm to be genetically engineered to resist disease, at the University of Abertay Dundee. It was an ideal subject for such an experiment, as its sterility meant there was no danger of its introgression into the countryside.