Out of 92% of the sites surveyed in England and all of Wales the presence of ‘Ash dieback disease’, caused by the Chalara fraxinea fungus, has been reported at 115 sites, and seven sites in Scotland. It is characterised by loss of leaves and crown dieback, possibly leading to tree death. Trees in forests, urban areas and nurseries have been reported to become affected and die not just in the UK but in the rest of Europe as well. The pathogen was newly identified after the first cases were reported in Poland in 1992, where trees were reported to die in large numbers. This disease has the potential to devastate the country’s landscape, especially since it appears to be too late to prevent its establishment in the UK. Trees confirmed to have the disease have been felled across all these sites. ‘Biosecurity’ is being enforced in areas where the disease has been reported as visitors are asked to wash shoes, bicycle and car tires before they leave the area to try and prevent its spread. The ash tree is a unique tree and an important part of the ecosystem, and some fear that if they become extinct some other rare species may become even rarer.