Ash dieback, ‘Chalara’, caused by the fungus Hymenoscyphus fraxineus, is thought to have been introduced to the UK in 2012 on imported ash trees (which were cheaper than home-grown!). It is predicted to have a devastating impact on our ~150 million native ash trees (Fraxinius excelsior), the second most populous tree species in England, and the most populous tree outside woodlands. As much as 98% of the population might be wiped out, along with populations of 1058 plant and animal species (plus 582 lichen taxa) it supports, of which 440 are classified as obligate (i.e. live only on Ash trees).

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The ash tree is also deeply woven into our culture – incorporated into hundreds of place names, our surnames - and its timber is highly valued for its strength, toughness, flexibility, and attractiveness. It has been the material of choice for tool handles, cricket stumps, furniture, and even aircraft frames, and is also an excellent firewood - even burning when green.

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The Chalara fungus, the fruiting body of which is a small white mushroom, causes the leaves and twigs to brown and wither. Sadly, no cure has been identified, but some isolated populations might survive - as happened when the English elm was virtually wiped out by Dutch Elm disease - and some trees might prove resistant and able to be used for restoration projects. So how should we respond to this significant change to our environment? And how can we most effectively utilise the large amounts of timber that will become available?

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