Data entry for the OPAL Tree Health Survey is now closed. However, survey resources and identification guides can still be downloaded for free below.
Thank you to all those who took part in the survey!
Survey data submissions can be viewed on the OPAL Data Explorer. In addition, Tree Health Survey data will soon be available for download from the OPAL website.
Trees are vital – bringing nature into urban areas, supporting the rural economy, providing food and habitats for wildlife, and helping to combat climate change.
However, our trees are under threat. The number of pests and diseases attacking them has increased in the last few years.
The best time to complete this survey is between May and September.
How to take part
- Step 1 – Download and print the survey documents in English or in Welsh (ideally in colour).
- Step 2 – Find a site with safe access to one or more broadleaved trees and start surveying.
Learn more about pests and diseases that can affect trees.
- Tree Health Survey Booklet (PDF, 1.8MB)
Survey instructions and information about the most common UK tree species.
- Tree Identification Guide (PDF, 1.2MB)
Recording sheets and information on the pests and diseases to look out for.
- Tree Pest and Disease Identification Guide (PDF, 1.8MB)
Pests and diseases that could pose a serious threat to UK trees.
By downloading this survey you agree to the terms and conditions for the OPAL Tree Health Survey
- Tree ID guide and poster (PDF, 2.4MB)
A guide for your wall to help you identify common UK tree species.
- Tree Health Survey recording sheet (PDF 177.91 KB)
Easy-to-print (black & white).
Looking for the Welsh language survey pack?
- Visit the Tree Survey page in Welsh.
Group leaders and schools
Download our group leader support guide, example risk assessment, and our new recording sheets for schools.
Note: You may download these documents for use in the context of the OPAL project only. All other rights are reserved.
Did you know?
Knopper galls, which can form on acorns, are caused by a tiny wasp called Andricus quercuscalicis. It arrived in England in the 1950s and has now invaded most of the UK.
A good biosecurity routine can reduce the risk of spreading diseases and invasive species.
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Tree ID guides at your fingertips:
To find out about the action being taken by UK governments and their agencies to protect our trees from pests and diseases, visit: