ATI data guide for planners and developers
The Ancient Tree Inventory (ATI) is a citizen science project led by the Woodland Trust and our partners, the Tree Register and The Ancient Tree Forum. The purpose of the ATI is to establish and record where our oldest and most characterful trees are so that we can locate ancient tree hot spots, identify threats, monitor losses, and develop better conservation strategies. The ATI is the UK's most comprehensive database of ancient, veteran and other notable trees, although it is far from complete. While the ATI is a helpful tool for identifying the location of these important trees, it should be noted that the ATI is a citizen science project and is dependent on the addition of records by the UK public, as well as by Woodland Trust volunteers and staff.
Anyone can register and add an unverified tree to the ATI map. When a tree is recorded on the ATI, it remains hidden from public view until it has been assessed by one of our specialist volunteer verifiers to determine the appropriate classification. It will then either be confirmed as ancient, veteran or notable (as appropriate) or the entry will be removed and the recorder notified that the tree did not meet the criteria for ATI registration.
Volunteer verifiers are trained to use a ‘combined assessment’ approach to assess what classification a recorded tree should be given. This considers multiple factors such as species, girth, presence of veteran features (e.g. trunk/branch hollowing, deadwood in canopy, cavities, decay fungi), tree habitat/location, tree form (e.g. maiden, pollard, coppice) and other environmental or human factors that may have affected its growth. Verifiers are encouraged to consider as much supporting evidence as possible when assessing a tree, including past historic management and land-use. Verifiers can also do a remote assessment of the tree if the tree record is has a complete condition assessment and contains images.
It is also important to highlight that these classifications do have to be assessed on a qualitative basis, i.e. there is no strict 'boundary' between these classifications. The overall classification of a tree is a judgement made by the volunteer verifiers based on the available evidence gained from the tree's measurements, condition, and historical context.
For example, a key function of the term ‘veteran’ is to capture trees that have exceptional habitat value, and often these trees will also have a high cultural and heritage value. The term is not a true ecological grouping, rather it serves to help identify trees which are important for biodiversity in their own right, and as part of a wider assemblage; veteran trees are important for the accumulation of features that are unable to be replicated within our lifetime. Identifying and evaluating veteran features requires the application of knowledge, experience and judgement.
The Woodland Trust has published guidance on how to assess ancient and veteran trees, which can be found here: Recognising and Categorising Ancient and Other Veteran Trees. We consider that girth alone cannot be used to assess veteran status, though there are approximate girth guidelines for 10 common species that verifiers use to inform their decisions provided here: https://ati.woodlandtrust.org.uk/how-to-record/species-guides/. Furthermore, an overview of the ancient, veteran and notable categories can be found on our website here: https://ati.woodlandtrust.org.uk/what-we-record-and-why/what-we-record/.
Ancient and veteran trees are protected under planning policy, so recognition of a tree’s veteran status may help to protect it from development. But the fact that a tree is registered on the ATI does not in itself provide any form of automatic protection.
While the ATI can provide indication of the presence of veteran trees, it is important to note that the absence of a tree from the ATI is not evidence that a tree is not veteran. It is estimated there could be up to ten times the number of ancient and veteran trees currently registered on the Inventory (Nolan et al, 2022). The fact that a tree is not currently recorded currently on the ATI does not prove anything in relation to its veteran status, it simply reflects the logistical realities of a citizen science project.
We hope that our ATI data can be used positively by the planning and development sectors to aid protection, and prevent the destruction, of ecologically important trees. It is open to anyone, at any time, to add a tree to the ATI map regardless of planning considerations in relation to the land. However, the ATI should not be viewed or used as a replacement for site-specific ecological and arboricultural assessments carried out by a VET-certified arborist in relation to planning proposals. Accurate and comprehensive baseline site assessments are still required for planning applications, so that the planning authority can properly assess the potential impacts of a development proposal on ancient and veteran trees and determine whether identified impacts can be feasibly mitigated.
