Celebrating 12 years of Observatree

Twelve years, 30,000 reports, 800 volunteers and still going strong

January 2026 marks my tenth anniversary as the Observatree project manager. When I was asked to take on the role, Observatree was just over two years-old and still in the process of proving its ability to make a positive contribution to tree health surveillance and monitoring. And here we are, another ten years later.

So why are we still here? What are the secrets to our success? Below are my reflections on what I believe has enabled us to continue ten years on, whilst still looking to the future.

1. People – From the volunteers, project staff and the colleagues that we work with across the Partnership, our Associates and others that are keen to learn about and share the messages of tree health.

2. Evolution – Since the project began, we have added the reporting of Sentinel Trees and added new pests and diseases to our resources.

3. Co-design – We include representatives of our volunteer network in many aspects of the project, including the development of new systems, processes and on the project Board.

4. Investment in systems – During the lifetime of the project, volunteer management systems, the website and tree health reporting systems have been updated and improved.

5. The right Partners – We have a good balance of interests and perspectives from government (GB and Devolved), national charities and research organisations to bring together the expertise in volunteer management, woodland ownership and lots of tree and plant health knowledge. And we continue to expand our network of collaborators through our Associate organisations who help to share our tree health messages.

6. Continued funding – We are exceedingly fortunate and grateful to have had a sustained level of funding that has allowed us to continue our work. My thanks to our partners for their ongoing support.

7. Quality – Both the training that we provide to our volunteers and the resources that underpin their activities are developed by tree and plant health professionals to ensure that they are incorporate the latest research and policy information.

8. Reputation – Thanks to the quality, knowledge and enthusiasm of our volunteers, their activities and the quality of the Observatree resources, the project has become established as a good source of tree health information and our volunteers are often asked to support other tree health research projects.

9. Communications – The vast majority of our tree health resources are freely available on our website where we regularly post blogs on the latest tree health news. And our quarterly eNewsletter continues to grow in the number of people signed up to receive it. We work with our Partners and Associates to raise awareness of tree health and promote surveillance and reporting.

10. Time and experience – Some of our volunteers have been with the project since it began. And many have been with the project for several years. We have many highly experienced volunteers within our network who are also able to support new recruits when they join, helping to further develop the core capability of the project.

Last winter, we added more that 70 new volunteers to the Observatree family and whilst we have retained volunteers for many years, some have left the project for a variety of reasons, freeing-up spaces for others. To date, more than 800 people have passed through the Observatree induction. Our former volunteers may no longer be ‘on our books’, but they are still aware of tree health, know where to find information and how to report anything of concern. Any one of them could still spot a pest or disease of concern and report it through TreeAlert.

During 2025, our volunteers submitted 3865 tree health reports, bringing our total over the past 12 years to more than 30,000. Of the 2025 submissions, 867 were Healthy tree reports, 2295 reports were submitted on the 649 Sentinel trees that are routinely checked by the volunteers and 703 reports were submitted for a diagnosis. These latter tree health enquires included 175 on our Priority Pests and Diseases. Whilst Observatree volunteers are trained on a Priority list, during the last year, the volunteers submitted over 120 other types of pest, disease, or symptom of an unknown cause of ill-heath to the diagnosticians within Forest Research. In terms of the network potentially spotting something new or unexpected, this is an incredible achievement and provides a clear example of why Observatree and our volunteer network continues to be a success.

Table 1 shows the most reported Healthy and Sentinel trees during 2025, with oak topping both lists. Elm zigzag sawfly was the most reported pest, a position previously held by both Oak processionary moth and Oriental chestnut gall wasp; whilst chalara dieback of ash continues to top the list of diseases, followed by increased reporting of the European mountain ash ringspot-associated virus.

What will top these lists during 2026? Will Elm zigzag sawfly continue to spread? Will Plane lace bug be spotted in new areas? Will the parts of Britain thought to be free of Chalara dieback of ash remain so? Will something new or unexpected be found? It is certainly reassuring to know that Observatree volunteers will once again be on the lookout. But we all have a role to play in supporting this surveillance and reporting through TreeAlert. And don’t forget, healthy trees can also be added. So, if you haven’t registered and added some information about your local trees, why not give it a go.