An out-of-season awakening

Trees across Britain are behaving as if spring has arrived, months before their time. Chris Nichols, head of conservation outcomes at the Woodland Trust, said mild autumn weather meant horse chestnut trees were flowering and showing signs of next year's spring growth more than six months early. Experts warn the phenomenon could harm pollinators in the long term.

The unusual run of warmth behind it is well documented: October was warmer than average across all parts of the UK and marked the ninth consecutive month with above-average mean temperatures.

"It's crazy, everything is so out of whack," Nichols said.

Stress, not a second spring

Dr Kate Lewthwaite, citizen science manager at the Woodland Trust, said trees flowering early is a sign of stress. Her suspicion is that drought during the summer's extreme heat made trees shut down essential systems as they would in winter - many wilted and lost their leaves prematurely in what amounted to an early autumn.

"When the rains came, it encouraged them to start spring flowering out of season," she said.

The consequences could be severe. Lewthwaite said this could kill whole trees or leave them forced to resprout from dormant buds on the trunk or branches, which would shrink next year's canopy. Nichols added that it is like an ecological mismatch with insects, concerning for the resilience of trees in the long term.

Kew sees the same pattern

The picture is the same at Kew Gardens, where Kevin Martin, head of tree collections, said trees in the arboretum were also going into early spring. In his account, trees went into dormancy this summer and, with the warm mild conditions, are now going back into growth - meaning they will lack buds when spring actually arrives.

Martin said the true impact of this will not be known until spring 2028.

A hard year for Britain's trees

The out-of-season flowering caps a damaging year for the country's trees:

• •Experts said England's ancient oak trees were dying as a result of high temperatures and drought.
• •Earlier in the summer, experts warned that high winds potentially associated with El Niño could cause widespread mortality among tree species weakened by heat and drought.
• •Martin said this was observed during Storm Austen and Storm Boelo, with an increase in failures compared with what would be expected during storms recording such wind speeds.
• •He also said trees have put on little growth, especially in the south-east where the drought has been really significant, so storms will cause more failures.

Scientists say the above-average temperatures behind these events are only possible due to the climate crisis, primarily driven by the burning of fossil fuels. Lewthwaite called for action to make woods more resilient, such as rewetting woodland and slowing the flow of the rains the country does get.