Scottish Wych Elm - History and Future Prospects
- Wych elm has grown in Scotland for the past 8,500 years
- In Britain more than 20 million elms have been lost since 1970s
- Dutch elm disease is spreading in Scotland
- A small proportion of wych elms appear to be able to survive
A Native Scottish Tree
The wych elm is one of only about 15 large trees that are native to Scotland. As with many native trees it supports a wide variety of other wildlife from insects to lichens and fungi to mosses. It is a natural component of Scottish woodlands in the lowland and highland zones, and has been here for at least 8,500 years according to preserved pollen.
Dutch Elm Disease
Since the 1980s Scotland’s elms have been under attack from a deadly fungus called Dutch elm disease – so called because Dutch scientists were the first to understand the disease. Although no accurate figures exist it has been estimated that Britain has lost over 20 million elms since the 1970s. The landscape, economic and wildlife impact has been enormous in England. Scotland has fared better because the disease entered at south coast ports in infected logs and has been spreading north ever since. The main areas of elm loss so far have been the borders, the central belt and the east coast.
In affected areas the loss of elms is rapid and at first sight appears to be total. The fungus spreads rapidly from tree to tree by hitching a ride on an otherwise fairly harmless elm bark beetle. When the next generation of beetles emerge they can transmit fungal spores to healthy trees through feeding on the bark of young twigs high up in the canopy. An elm that is healthy in spring can be dead by mid summer.
Signs of Recovery
The most encouraging observation from areas where Dutch elm disease has progressed unchecked is that a small proportion of trees appear to show natural resistance. Quite how they manage this remains unclear. The fact that survivors exist should not be a surprise. Genetically diverse populations may contain, by chance, individuals with some sort of advantage. What we are witnessing is natural selection and evolution in progress.
The Royal Botanic Garden Edinburgh has successfully propagated wych elms that show disease resistance by taking cuttings. These trees will be planted as part of the Wych Elm Project and offer the potential for future research into Dutch elm disease.
