The study analysed ash dieback damage on 16-22 year old trees in Swedish woods and found that the disease is strongly genotypically controlled, meaning that it attacks ash trees that display the same or similar genetic properties.
On Monday, a ban on UK imports of ash trees came into force.
The study found:
• Ash survival is strongly heritable
• Little is known about H. pseudoalbidus (the disease-causing pathogen discovered in 2010) but genetic diversity will provide a buffer against new diseases
• Faster growing clones are less susceptible to ash dieback as rapid growth restrains the disease
• 90 per cent of ash trees died in a similar study in Lithuania (2005-10)
• Forested area of Lithuania fell from 53,000 ha to 38,000 ha (2001-2009)
• Government investment is needed to support ash breeding programmes