Using 3D modelling to safeguard the UK’s ancient and veteran oaks.
There are more ancient and veteran oaks found in England than the rest of Europe combined. These special trees are fundamental components of our landscape, providing habitat for many wildlife species, storing carbon and representing our cultural and historical heritage.
In 2022, our conservation research programme funded a research project to provide new insights into the architecture (or structure) of ancient and veteran oak trees in the UK using LiDAR (light detection and ranging) technology. Named SCATTER: Scanning Ancient Trees with Terrestrial LiDAR, the project used cutting-edge terrestrial laser scanning techniques to measure the structural characteristics of ancient and veteran trees. These scans have been used to generate a unique digital archive of 3D models which will help us better understand and manage these living legends for the future.
The main goal of SCATTER was to build a digital archive of ancient and veteran oak trees and characterise their shape, size and form to understand the similarities and differences in their architecture. The project examined ancient oaks belonging to two species: pedunculate oak (Quercus robur) and sessile oak (Quercus petraea).
Within this goal, we had three key aims:
Ancient and veteran oak trees have particularly interesting architecture because of their long cumulative life histories, which leads to divergence between individual trees’ structures. A tree’s architecture is shaped by its individual genes and the evolutionary history of the species, as well as physiological responses to its local environment and ecological or anthropogenic changes to its nearby surroundings. Age-related physiological changes – such as reductions in annual incremental growth, fragmentation of the stem, crown retrenchment and dieback, and the development of decay features – can also influence a tree’s architecture.
The SCATTER project team scanned approximately 40 ancient and veteran oak trees using LiDAR to create detailed 3D images of the trees. In the picture below, you can see the complex branching structures and tree hollows of the Wyndham's Oak, which are often important features of ancient and veteran oak trees.
The 3D models of the trees scanned during the SCATTER project have been placed into an open-access research repository, named Zenodo, where it will be free for anyone to use. This digital archive of important ancient and veteran oaks can facilitate research, contribute to ancient and veteran tree conservation and digitally preserve our cultural and historical heritage.
To create these impressive images, terrestrial LiDAR instruments are positioned below and around the tree canopy. These instruments send out rapid pulses of light which are reflected off the tree trunk, branches, leaves, ground and other objects in the surrounding environment. When these pulses hit part of the tree, they return to the LiDAR instrument, allowing very accurate distance measurements to be made. Millions of pulses of light are used to create the precise 3D image that you can see above.
The SCATTER team also used other tools to measure the ancient oaks, including 360 videos using an Insta360 camera, and close-range LiDAR and photography using an iPhone. Close-range LiDAR captured important features and details of the trees which were hidden from terrestrial LiDAR. As the device is smaller, it also allowed researchers to scan smaller and more detailed areas of the tree, such as inside a hollow and the tree trunk. If you have an iPhone 12 Pro model or later, you can have a go at using LiDAR to create 3D models. Go outside and try scanning flowers, logs or even tree trunks.
Here are just a few examples of how the models can be used to protect these trees and the old oaks of the future.
Credit: WTML
LiDAR technology is a useful tool for monitoring and aiding assessments of ancient trees and may provide insights for management decisions, including limb mass estimates for propping and bracing and understanding the trees’ response to management interventions. We’ve created guidance documents to describe our approach to conserving ancient and veteran trees.
Credit: Cecilia Chavana-Bryant
The 3D models can be used to examine the structural similarities and differences between individual ancient and veteran oaks with different life histories (for example: species, location and management history). These structural traits include woody volume, leaf location, branch length and branching pattern, and decay features such as deadwood in the crown and cavities. Further understanding structural traits may also help us predict which younger trees have the best chance of growing into ancient and veteran trees in the future.
Credit: Papilio / Alamy Stock Photo
A particularly important use of the SCATTER data is that it will provide much more effective carbon assessments. Existing methods for carbon assessments are not appropriate for ancient and veteran trees, and this project will allow for better estimates and improved accuracy of the models predicting carbon stored in structurally complex old trees.
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Contributors
Grant recipient: Dr. Phil Wilkes, RBG Kew Wakehurst (formerly Department of Geography, University College London (UCL))
Project Team: Dr. Cecilia Chavana-Bryant, Department of Geography, UCL, Prof. Mathias Disney, Department of Geography, UCL and NERC National Centre for Earth Observation (NCEO).
Project Partners: Robert Warnock (The Ancient Tree Forum), Vikki Bengtsson (Pro Natura, Senior Ecologist), Emma Gilmartin (Arboricultural Association, formerly Woodland Trust).
