Threats to Dulwich Trees - Ash Tree Die Back
by Jill Manuel
There has been a great deal of news in the media of an alarming threat to our ash trees. South East England is the most wooded part of the UK. Our 80 million ash trees make up almost a third of these woods, and particularly on the calcareous soils in the Midlands for instance, the loss of the local native ash would have a devastating effect on the whole appearance of the landscape.
Ash die-back is a fungal disease (chalara fraxinia), not insect caused. It was first observed in Poland in 1992 and in the last 20 years or so has moved inexorably across north- western Europe, being found now in Germany, Scandinavia and the Netherlands, where it is reported recently there has been a terrible loss with 80-90% of the ash trees dead or dying. There is some evidence from Europe that the beautiful Manna Ash (Fraxinus ornus) is affected too, being also part of the natural host range of this fungus.
The Forestry Commission has announced that this fungal growth disease has now been found at a number of sites, though forested areas are more likely to be susceptible. The disease may have come from the importation of stock from the Continent which is a very significant source of plant material used in the UK for both large and private schemes.
Ash is also found growing in hedgerows, and once infected these can act as a corridor of infection from the wind blown fungal spores. We all remember favourite views utterly changed by the loss of the elms. For Ash to succumb would leave us with a truly stricken countryside.