Earth observation for the improved management of tree health in urban and peri-urban settings

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Trees and forests are a key provider of multiple ecosystem services to the UK, as well as having commercial and cultural value. However, UK tree and forest health is under pressure both from climate change and from introduced pests and diseases. While commercial forestry operations are fairly well mapped, smaller woodland blocks and individual trees in agricultural, private, urban and peri-urban settings are less well recorded. In order to understand the sensitivity and resilience of such trees and woodlands to potential pressures on tree health it is important to understand their location and composition. A recent report by the Tree Council into the national response to ash dieback highlighted the problem of not having a national tree inventory, with estimates of the UK non-woodland ash tree population ranging between 27 and 60 million trees.The overall objective of this project is to develop a scalable tree species distribution map for urban and peri-urban environments to support policy decisions related to managing tree health. Such a tree map would be of use to multiple stakeholders who benefit from ecosystem services derived. These range from national and local government, to conservation charities and academia, to other managers of estates (in the broadest sense which includes business centres, education facilities, NHS etc.) and utilities that have to manage the tree stock. This project aims to produce these maps by analysis of high resolution satellite imagery from the Copernicus Programme Sentinel satellites trained on very high resolution imagery from unmanned aerial vehicles (UAVs) and ground based surveys. The second half of the project will focus on the delivery of these maps using web technologies, which would include contextual mapping of ecosystem service provision, cultural value and sensitivity to pest, disease and climate pressures.The commercial product that will be developed by this project is a mapping service. Ultimately we would see this developing into a national woodland map. However, the output for this project will be a proof of concept map for a single council area. This will be delivered as a licenced web mapping service which can be consumed by bespoke applications or off-the-shelf GIS software. On top of this we will build web and native OS applications that display not only the tree species distribution maps, but also allow visualisation of socio-economic values for amenity woodland and interaction with the woodland mapping dataset.The key stakeholders for tree distribution mapping service are Defra, the Animal and Plant Health Agency, local government agencies, charities and community groups concerned with trees and tree health. If future responses to invasive pests and diseases follow the same model as the response to ash die back, then the management of infected/infested trees will be the responsibility of local authorities and action groups. Tree distribution maps based on the methods and technologies delivered by this project would provide local estimates of numbers and locations of different tree species, allowing for more effective short and long term planning to maintain tree health, a reduction in survey costs and a reduction in the time to implement management actions in response to pest or disease outbreaks.