A significant threat to our iconic British trees is the increasing incidence of imported pests and diseases that damage native plant species. In recent years the UK has seen outbreaks of Chalara dieback of ash, horse chestnut leaf miner, bleeding canker of horse chestnut, oak processionary moth, oak decline, larch tree disease and sweet chestnut blight, to name a few. These organisms have all had a catastrophic impact on our trees and have caused irrevocable changes to the British landscape.

The IPSN supports surveying and monitoring of British tree species in botanic gardens and arboreta around the world. This offshore monitoring of our native plants, or so called ‘sentinel plants’, provides an early warning system to identify damaging organisms before they arrive in the UK. If we know these organisms are coming, we can prevent them arriving in the UK or better manage outbreaks if they do arrive. The network trains garden staff in the UK to improve identification and responses.