Scientists at the Universities of Southampton, Cambridge, Oxford and St Andrews have conducted a review of tree disease outbreaks. The review, The consequences of Tree Pests and Diseases for Ecosystem Services, found that the beneficial services provided by trees are under threat from increasing pest and disease pressure around the world.

Published on Friday in the journal Science, the research revealed that widespread death of trees from diseases such as from Dutch elm and fungal ash disease Chalara fraxinea, which arrived in the UK last year, has not been limited to the UK. Rather, as globalisation and climate change continue, the risk of spreading diseases may increase further.

The researchers warned that, "in particular, high volumes and new forms of trade… may increase the risk of disease spreading and provide opportunities for genetic reassortment which can enhance … the ability of an organism to cause disease."

Trees and forests provide a wide variety of ecosystem services in addition to timber, food, and other provisioning services, such as carbon sequestration, flood risk reduction, wildlife habitat and leisure use. Scientists working together on the analysis said new approaches to pest and disease management will be needed, ones that take into account the multiple services trees provide, as well as the different stakeholders they benefit.

Even so, identifying all species that may become pests will be virtually impossible, and so the researchers stressed the importance of risk management at "pathways of introduction", especially where modern trade practices provide potential new routes of entry for pests and pathogens.

Peter Freer-Smith, a visiting Professor at the University of Southampton and author of the paper said, "Modern pest and disease management for plants and the natural environment needs to be based on an extensive science base. We need to understand the molecular basis of pathogenicity and herbivores, as well as why some species reach epidemic prevalence and abundance."

Researchers also explored the difficulties of maintaining tree health and considered the consequences of pests and diseases for the full range of ecosystem services provided by trees. Many of the benefits from woodlands and forests, including carbon storage, maintenance of biodiversity and recreational use, are 'free of cost' and enjoyed by a range of 'stakeholders' – this, they said, raises difficult questions about who should be responsible for measures to protect tree health.