A big THANK YOU to all citizen science volunteers!
Alex Marshall, 10/06/2026
There are thousands of volunteers taking part in our 3 Citizen Science Projects; Observatree, Nature’s Calendar and the Ancient Tree Inventory. Whether they are identifying signs and symptoms of tree diseases, measuring the girth of an ancient tree or recording the first signs of the changing seasons, every single data point recorded contributes to an invaluable database. Here’s a little bit more about what our citizen scientists have helped to achieve for each of the 3 projects:
Nature’s Calendar
• Funded by People’s Postcode Lottery donations, Nature’ Calendar is a project all about recording the timing of the seasons! Nature’s Calendar is featured annually in the Met Office State of the Global and UK Climate reports, it’s invaluable in tracking nature’s response to the pressures of warming temperature and climate change. In 2025 we had 27 requests for the data from scientists, authors and students studying the impacts of climate change on nature.
• Also in 2025, there were 2500 new registrations, 9000 new records and 3700 hours given to the project.
• Year on year (and year-round) Nature’s Calendar insights are one of the biggest PR generators for the Woodland Trust. For example, a BBC Radio 4 interview September 2025 had a potential audience of 3 million people.
Recording hawthorn first leaf tinting. Credit Alex Marshall WTML
The Ancient Tree Inventory
• The Ancient Tree Inventory (ATI) aims to map and record ancient, veteran and notable trees. At present, volunteers have contributed to over 240,000 verified records and it is the most complete database of ancient and veteran trees in the UK. Many of these trees sit outside of protected areas so understanding where they are and their significance for both people and wildlife is key to protecting them from harm.
• Verifying is a process by which volunteers check and validate records and categorise them as either ancient, veteran or notable. In 2025 volunteers 168 volunteers verified 17,283 records. Hundreds of ancient trees with immense biodiversity and cultural value are discovered each year.
• ATI has been a paramount resource to properly valuing ancient and other veteran trees and have resulted the reversal of dozens of planning applications which would have resulted in the trees’ partial or complete destruction.
• The ATI has also consistently been a resource for finding contenders for the UK and European Tree of the Year competitions.
A volunteer measuring tree girth for the Ancient Tree Inventory. Credit Michael Heffernan WTML
Observatree
Research shows that Observatree volunteers contribute around half of all the Tree Alert reports submitted by the public. They are highly regarded by tree health professionals due to their skills, experience and ability to recognise priority pests and diseases. This is aided by both their high level of training and the fact that they survey areas that are known to them so they are able to monitor subtle changes over time.
In 2025, Observatree volunteers volunteer 4028 hours and submitted 3868 reports.
In recent years Observatree volunteers have…
• Spotted and reported the occurrence of ash dieback for the first time in dozens of 10km2 grid squares on the Defra Chalara distribution map (especially in Wales and Scotland), adding important information on the distribution of this disease.
• Responded to an urgent call for data regarding Plane Lace Bug, which yielded reports within 24 hours.
• Working to monitor oak processionary moth (OPM) across central and south east England. Including on average 40 sites annually on WT estate, enabling site teams to take action.
Observatree volunteers at a training event at Clumber Park. Credit Alex Marshall WTML
As you can see, our citizen science volunteers are exceptional! We wanted to say a huge THANK YOU this volunteer’s week!
