Oak Trees Rely on Root Microbes to Adapt to Drought

Study finds mature oak trees maintain stable microbiomes despite environmental stressors

Published on Feb. 12, 2026

Got story updates? Submit your updates here. ›

A study observing 35-year-old oak trees in a natural woodland found that the trees' above- and below-ground microbiomes were resilient to drought, nutrient scarcity, and exposure to pathogens. The trees showed subtle changes to their root-associated microbiota after prolonged drought, suggesting they can recruit beneficial bacteria under stressful conditions to aid in adaptation.

Why it matters

As climate change accelerates, understanding how long-lived tree species like oaks can adapt their microbiomes to environmental stressors is crucial for maintaining forest ecosystem stability and the trees' role in carbon sequestration.

The details

Researchers experimentally manipulated the environmental conditions of 144 oak trees, building rain-excluding enclosures to simulate drought, ringbarking trees to simulate water and nutrient scarcity, and inoculating some with bacteria and beetles associated with a fatal oak disease. They found the trees' microbial communities remained largely stable, with only subtle increases in drought-tolerant bacteria and growth-promoting microbes in the roots after prolonged rain exclusion.

  • The study was published on February 11, 2026 in the journal Cell Host & Microbe.
  • The researchers collected samples from the oak trees over the course of two years.

The players

James McDonald

A microbial ecologist at the University of Birmingham and senior author of the study.

Sandra Denman

A plant pathologist at Forest Research (Forestry Commission UK) and senior author of the study.

Usman Hussain

A microbiologist and molecular biologist at Bangor University and the University of the West of England, and the first author of the study.

Cell Host & Microbe

The scientific journal that published the study.

Got photos? Submit your photos here. ›

What they’re saying

“As environmental stressors are increasing, one of the key adaptations that trees have is their microbiome. If we can get a more mechanistic understanding of how host-microbe interactions help trees navigate and tolerate drought, it might open up the opportunity to improve tolerance, for example by inoculating trees with beneficial microbes.”

— James McDonald, Microbial ecologist (Cell Host & Microbe)

“Climate change is happening really quite rapidly, but trees are long-lived, sessile organisms that take a long time to adapt to changes, and many of our trees are not well equipped.”

— Sandra Denman, Plant pathologist (Cell Host & Microbe)

“Even as the trees were showing physiological changes and the soil was becoming a lot drier, their microbiome remained quite stable. This highlights a potential role for oak-associated microbial communities in maintaining forest ecosystem stability.”

— Usman Hussain, Microbiologist and molecular biologist (Cell Host & Microbe)

What’s next

The research team plans to investigate the molecular mechanisms that allow microbes to endow their oak tree hosts with increased resilience, and to compare how tree microbiomes change over the course of their long lifespans in different locations.

The takeaway

This study demonstrates the crucial role that tree microbiomes play in helping long-lived species like oaks adapt to rapid environmental changes, underscoring the need to better understand these complex host-microbe interactions to support forest ecosystem stability and carbon sequestration in the face of climate change.