Identifying individual drivers of damage to oak during severe UK storms in winter 2021
Date: August 2025
Timescale: 2021-2025
Organisation: Newcastle University, Forest Research, Northumbria University
Lead researcher(s): Kate Halstead, Roy Sanderson, Salvatore Bonomo, Christopher Quine, Andrew Suggitt, Rachel Gaulton
Synopsis
In late November 2021, Storm Arwen brought northerly winds exceeding 40 metres per second to the UK, with the worst damage recorded in Northumberland and Scotland. The storm caused widespread damage to homes, infrastructure and woodlands, with oak trees among the most affected and many notable and veteran specimens lost. A second storm, Barra, followed soon after, though its impacts were far less severe.
Fieldwork was combine with tree-ring analysis, remote sensing and statistical modelling to identify the main drivers of storm damage to oak during the storms. The study focused on three sites in the North East of England, one of the regions worst affected. At Wallington Estate, Cockle Park Farm and Gosforth Nature Reserve we recorded oaks that had been damaged alongside those that remained intact. By comparing damaged and undamaged trees at the same locations, we aimed to identify the factors that made the difference. Tree structure was measured using terrestrial laser scanning, canopy health was assessed from satellite imagery, growth patterns were analysed from tree-ring cores, and field inspections recorded visible disease symptoms and structural defects.
The results showed that individual tree characteristics were much more important than broader site features in explaining storm damage. Structural defects such as weak forks, cavities and old pruning wounds were strongly associated with failure, and trees with visible disease symptoms were also more likely to be damaged, both because infection and decay weaken the wood itself and because they can reduce growth and overall vigour over time.
For managers and owners, the findings underline the importance of practical monitoring, especially of very old trees of interest such as ancient and veteran oaks. Inspections that record defects such as weak forks, cavities or pruning wounds, alongside visible signs of disease or decline, provide the clearest indication of which trees may be most at risk. Focusing attention on these vulnerable individuals offers a realistic way to anticipate storm impacts and to plan management that better protects oak across sites.
“Oaks are of exceptional ecological and cultural importance in the UK, supporting thousands of associated species and holding centuries of history in our landscapes”
Outputs:
Contact: Dr Kate Halstead, kate.halstead@forestresearch.gov.uk
3D point cloud of storm damaged oak, taken using a GeoSLAM ZEB Horizon LiDAR scanner, from which measurements of tree structure e.g. DBH, height, crown area, were extracted
