Threats from pests and diseases

Signs of Horse Chestnut leaf miner

Horse chestnut leaf miner is now common in the UK (Photo: Forestry Commission)

Our trees face huge challenges from pests and diseases. They threaten some of our most widespread native species such as ash and oak, as well as uncommon ones like juniper.

Pests and diseases affect woods and the wildlife that depends on them. They also affect trees in the wider landscape such as in parks, gardens, fields and hedgerows changing the face of our landscape.

We work to protect our most valuable woods and trees from pests and diseases through research, and partnerships with others and influencing policy. We only plant UK sourced and grown trees.

Observatree - monitoring tree health

This four year project has set up a new UK tree health early warning system using citizen science. By identifying tree pests and diseases at the earliest possible stage we can maximise the chances of eradicating or controlling an outbreak. 

Funded by the EU’s Life programme, Observatree is a partnership project. Led by Forest Research, the research agency of the Forestry Commission, and supported by Defra, partners are Fera, the National Trust, and the Woodland Trust.

More about pests and diseases

The increasing threat is due to a number of factors including the growth in international trade of trees and plants and the effects of climate change.

Find out more about UK tree pests and diseases

Trees face huge challenges

With more new pests and diseases reaching our shores tackling pests and diseases is now an urgent priority

Learn about the threats