However, almost all mature American elm trees have been killed in the last 50 years by Dutch elm disease, which is caused by a fungus, Ophiostoma novo-ulmi, introduced from Asia. Elm bark beetles ...

The fungal disease carried by the elm bark ... tree species I started thinking about elms more. All of a sudden, I was noticing elms hiding in hedgerows. It is the characteristic asymmetry of elm ...

He said the return of the elm is even more important given that ash trees face ash dieback and many will be lost, which is bad news for the lichens which grow on the bark of both the ash and the elm.