Tree Health Survey results

In the OPAL Tree Health Survey, our citizen scientists make general observations on tree species and also height and girth. They help to map the frequency and distribution of selected pests and diseases of oak, ash and horse chestnut trees. They also look out for and report six pests and diseases of most threat to the country. This was the first OPAL survey to directly support official government policy, specifically by engaging the public with tree health and supporting official surveillance. 

What have we found?

 The data submitted by OPAL participants shows that:

  • The horse chestnut was the least healthy of the three tree species surveyed, with the highest incidences of pests and diseases recorded
  • The distribution of pests and diseases across the country largely corresponded with results of other surveys
  • Two of the official 10km grid squares in which Chalara ash dieback was confirmed were found by OPAL participants
  • Over two thirds of people who participated in the survey said it was their first experience of working with trees

Tree pest and diseasechart
Prevalence of tree pests and diseases on oak, ash and horse chestnut (OPAL data, May 2013-November 2014) 

See results on the OPAL Data Explorer

Explore the OPAL Tree Health Survey results and draw your own conclusions. Use the OPAL Data Explorer to:

  • Map sightings of pests and diseases across the UK
  • Find out how healthy trees are near you 

View Tree Health Survey results on the OPAL Data Explorer (opens in new window)

View more results

Next steps