A recent, Swedish study in the Scandinavian Journal of Forest Research has revealed crucial information for horticulturalists in the UK, and in Northern and Central Europe, in their battles against the aggressive attacks of the Chalara fraxinea fungus (otherwise known as ash dieback disease) on mature forest areas. Results from the study are far reaching, encouraging governments to invest in ash breeding programmes that will all but eliminate the disease.
- Ash dieback damage on 16-22 year old trees in Swedish orchards analysed
- Findings indicate that the disease is strongly genotypically controlled, meaning that it attacks ash trees that display the same or similar genetic properties
- Scope for introducing breeding programmes to produce ash trees with greater resistance to infection
The research is more important than ever. October 29, a ban on UK imports of ash trees came into force before reports from BBC News indicated that 100,000 trees had been destroyed in an attempt to stop the spread of the disease.
Governments in Sweden, the UK and other affected countries need to act now or they could experience the same disease deforestation witnessed in Lithuania over the past decade, where forested areas dropped from 53,000 hectares to 38,000 hectares in just eight years. In a Lithuanian observation of ash orchards, similar to that of the Swedish study, 90% of the trees died (2005-10), this in the country where the disease was first documented in the early 1990s.
British Prime Minister, David Cameron should take note. On the day where The Daily Express reports that his country could be footing a £37m a day bill to the European Union (a meagre £13.6bn each year), the £3m funding cut to the Forestry Commission -- representing 25% of their overall annual budget -- seems like a drop in the ocean.
The Forestry Commission Trade Unions announced their disgust in 2011, stating the "cuts will severely compromise the FC's ability to retain a properly resourced forestry estate with protected access and services, and to protect biodiversity, wildlife and the environment." This opinion has now been realised with ash dieback sweeping the UK's forest population.
- Ash survival is strongly heritable
- Little known about H. pseudoalbidus (the disease-causing pathogen discovered in 2010) but genetic diversity will provide a buffer against new diseases
- Faster growing clones less susceptible to ash dieback as rapid growth restrains the disease
- 90% of ash trees died in a similar observation in Lithuania (2005-10)
- Forested area of Lithuania fell from 53,000 ha to 38,000 ha (2001-2009)
- Government investment needed to support ash breeding programmes
Mr Cameron and his counterparts across Europe must do something to stop this spread. The research suggests that this should be through financial action.
Did the £3m Forestry Commission cut lead to this problem in the UK? What will the eventual cost to the taxpayer be? Only time will tell. However, one conclusion that can be drawn from this research is that there is an answer to the ash dieback problem. Through stringent breeding programmes of stronger clones, ash trees with greater resistance to the disease can grow, meaning a reduced risk of a Chalara fraxinea fungus outbreak. For now, the government must deal with this problem but a sustainable plan for the future must be considered imminently.
- Lars-Göran Stener. Clonal differences in susceptibility to the dieback ofFraxinus excelsiorin southern Sweden. Scandinavian Journal of Forest Research, 2012; 1 DOI: 10.1080/02827581.2012.735699
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