Ancient oaks in England face growing threat from extreme heat

England’s ancient oak trees are increasingly dying under prolonged heat and dry weather, with conservation experts warning that trees and ecosystems are unable to adapt quickly enough to a changing climate.

The Woodland Trust said extreme summer conditions across Europe were putting significant pressure on trees and other plants. Many trees are responding to the heat and drought by entering an “early autumn”, wilting and shedding their leaves weeks or months ahead of schedule, according to The Guardian.

John Parker, chief executive of the Arboricultural Association, said: “The signs of heat stress and dry weather is visible.”

Ed Pyne, a senior conservation adviser at the Woodland Trust, explained that trees constantly transport water, minerals and nutrients from the soil through their roots and trunks to their branches and leaves.

“When the trees are losing too much water, it stops this process and that’s when we start seeing the leaves wilting and dying, which can give rise to this early autumn phenomenon where the trees are losing their leaves early,” he said.

Ancient and veteran trees are particularly vulnerable. Pyne said: “These really old trees, they’re survivors, but, like us, when they get old they get a bit less resilient.”

The death in June of the Major Oak in Sherwood Forest, one of Europe’s oldest and best-known trees, highlighted the severity of the problem. “One of the main reasons that tree died is because of these extreme weather conditions,” Pyne said.

Oaks are considered chronologically ancient from around 400 years old, although many develop ancient characteristics at about 300 years. England has about 3,300 oak trees measuring more than six metres in circumference, including around 114 measuring more than nine metres.

Sherwood Forest lost eight ancient oak trees in 2024 and 2025. Pyne has also identified seven ancient oaks in England and Wales that he considers to be in critical condition.

He warned that repeated drought was creating cumulative damage.

“When you get these incessant droughts year after year, it’s a cumulative effect which compounds across time and gets worse. Almost all of our ancient trees are struggling under these conditions. They’re dying of this drought stress.”

Pyne’s analysis suggests that half of England’s ancient oak trees could be lost over the next 60 years. Because the analysis did not account for the effects of a changing climate, he believes the actual losses could be significantly higher.

The threat extends beyond oaks. Parker said beech trees were also struggling with extreme heat and warned: “They are possibly going into decline and may die, which would be disastrous for us.”

Across Europe, even some drought-tolerant species such as pine are being affected. Alexander Held, a senior expert at the European Forest Institute, said: “Our trees can’t cope.”

Angelo Morgan, a director of urban tree management at Trees UK, said hot and dry conditions were also increasing the risk of branches breaking. “The tree’s vascular system isn’t taking up as much moisture as it would normally do and so a lot of the limbs become very brittle and a lot of larger limbs are failing,” he said.

Held said forests were constantly adapting to environmental changes, but the current pace of change was overwhelming their ability to respond.

“Our trees and ecosystems aren’t fast enough to cope with the speed of change. These changes will likely be a big disruption to our ecosystems,” he said.

By Sabina Mammadli