How Our Trees Are Responding to Stress

If you’ve taken a walk through the woods lately or even just looked outside, it wouldn’t be crazy to think autumn has already arrived. Berries are ripening weeks ahead of their usual time, leaves turning yellow, red and falling early, and so many acorns scattering across the ground – these are all scenes more typical of September or October. But this year, across much of the UK, these signs are appearing while summer is still in full swing but why?

A False Autumn

Experts are clear, this is not nature “running early.” Instead, these autumnal signals are stress responses triggered by heat and drought. When conditions become too harsh, many trees and shrubs react by shutting down, shedding leaves, and fast-tracking fruiting. It’s a survival mechanism. The trees way to conserve energy and ensure reproduction by pushing out seeds and berries before it’s too late.

For example, hawthorns and rowans are heavily laden with berries already. While birch and horse chestnut are dropping leaves months before their time. Oaks, too, are showing stress, with acorns of all sizes and colours dropping to the ground before they’ve fully developed.

The Wider Ecological Impact

This premature shift carries risks well beyond the trees themselves as wildlife depends on the natural timing of fruit and leaf cycles. Birds that rely on late-autumn berries for fuel before migration may find much of their food already gone. Small mammals like mice, hedgehogs and squirrels also risk losing crucial seasonal resources like food and even habitats.

“This early leaf drop is not the same as the natural autumn leaf fall, which is triggered by decreasing daylight hours and colder temperatures its triggered by extreme hot weather linked to Climate Change.” explains Alistair Griffiths, director of science at the RHS.

In effect, the natural calendar is out of sync. Trees are “preparing for autumn” long before the rest of the ecosystem is ready, disrupting the delicate balance between plants, animals and the seasons.

A Sign of Changing Climate

The phenomenon of “false autumns” has been observed more frequently in recent years, reflecting the broader impact of climate change on the seasons. Prolonged summer droughts and extreme heatwaves will become more and more common and trees are showing visible signs of stress.

Over time, these shifts in our climate could reshape our landscapes as we know them. Some species may struggle to survive repeated cycles of premature leaf drop, while others could adapt more quickly. The changing appearance of our hedgerows, woodlands and orchards is a reminder of the pressures climate change places on our environment.

What Gardeners Can Do

For those growing trees in gardens or orchards, there are small ways to help:

Mulching around the base of trees helps conserve soil moisture.

Planting a diverse selection of tree varieties increases resilience to climate extremes.

Watering young or newly planted trees during prolonged dry spells can prevent early dieback.

While we cannot control the weather, we can try to create conditions that give trees a better chance of withstanding these stresses and supporting the vast biodiversity along with them.

Looking Ahead

As we head into September, we may see these “false autumn” signs intensify before true autumn arrives. Whether early colour and fruiting become the new norm remains to be seen, but they are clear indicators that our climate is shifting and our trees are on the frontline.