OPAL Tree Health Survey

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.

Mike Dilger and chestnut tree

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.

UK governments have already stepped up their activity to protect trees, and you can help too, by taking part in the OPAL Tree Health Survey, designed in collaboration with Forest Research and FERA.

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.

Downloads - what you need to get involved

Survey pack

By downloading this survey you agree to the terms and conditions for the OPAL Tree Health Survey

Also available:

Looking for the Welsh language survey pack?

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.

Watch it

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.

Watch it

OPAL logoA good biosecurity routine can reduce the risk of spreading diseases and invasive species.

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Tree ID guides at your fingertips:

Policy and regulation

To find out about the action being taken by UK governments and their agencies to protect our trees from pests and diseases, visit: