Following the UK’s hottest summer on record, Storm Austen and Storm Boelo have brought widespread reports of fallen trees, disrupted transport networks and, tragically, loss of life. But could the drought and extreme heat experienced earlier this year have contributed to the damage we’ve seen? And what does this mean for how we understand and manage tree risk?
The recent storms have highlighted the vulnerability of trees across our highways and public spaces. While strong winds are the immediate cause of many failures, the conditions influencing a tree’s ability to withstand those winds can develop long before a storm arrives.
After months of exceptional heat and drought, the question is whether drought-stressed trees may have been more susceptible to failure when the first major storms of the season arrived.
What Does the Science Tell Us About Drought-Stressed Trees?
The UK experienced its hottest summer on record in 2026, alongside prolonged periods of dry weather. According to the Environment Agency’s drought update on 23 October, drought conditions remained widespread across England immediately before the storms, with severe drought affecting parts of the South West and South East.
The implications for tree health are well documented. Forest Research identifies several consequences of drought, including reduced growth, crown dieback, increased susceptibility to pests and diseases, and increased risk of windthrow – where trees are uprooted or overturned by wind.
Drought-stressed trees can experience changes in their physiological condition and resilience, with impacts that may persist beyond the period of dry weather. The severity depends on factors including species, age, rooting conditions and the duration of water stress.
Importantly, this means a tree’s vulnerability during a storm may be influenced by environmental conditions experienced months earlier, rather than simply the wind speeds recorded on the day.
Could Drought Have Contributed to the Recent Tree Failures?
The extensive tree failures reported during Storm Austen and Storm Boelo raise an important question: how much of the damage may have been influenced by the drought and extreme heat experienced earlier this year?
With Forest Research already identifying increased windthrow risk as a consequence of drought, there is good reason to consider whether drought-stressed trees were more vulnerable when the storms arrived.
Forest Research’s guidance on windthrow identifies soil conditions, rooting characteristics, drainage and exposure as important influences on tree stability. Prolonged drought can affect tree health, while subsequent periods of heavy rainfall and waterlogged soils can reduce root anchorage. The interaction between these conditions and strong winds may therefore influence the likelihood of failure.
The timing of the storms also matters. Trees retaining their leaves during autumn present a greater surface area to strong winds, increasing the forces acting on their branches, stems and roots.
Taken together, these factors suggest that the damage caused by a storm cannot always be understood through wind speed alone. The condition of trees, the environment around them and the weather experienced in the preceding months can all influence how they respond.
What Does This Mean for Tree Risk Management?
For local authorities responsible for managing thousands of trees alongside highways, public spaces and critical infrastructure, the implications extend beyond the immediate storm response.
Tree inspections and risk assessments already consider structural condition, defects and the consequences of failure. However, periods of exceptional drought and changing environmental conditions reinforce the importance of understanding how that risk may evolve between inspections.
A tree assessed before a prolonged drought may have experienced significant environmental stress by the time the next inspection is due. Understanding which trees are potentially more vulnerable, where they are located and what the consequences of failure could be can help authorities prioritise further assessment and intervention.
This is where reliable tree inventories, condition records, environmental information and risk-based management become particularly valuable. Bringing that evidence together supports more targeted inspections and maintenance, focusing limited resources where they can make the greatest difference.
At KaarbonTech, we support local authorities in understanding their tree assets, condition and risk, helping them develop evidence-led inspection and maintenance programmes that account for the wider environment and the places those trees affect.
The question isn’t simply whether this summer’s drought contributed to the tree failures we’ve just witnessed. It’s whether we’re doing enough to understand how the conditions our trees experience today could influence the risks they present tomorrow.