From YALE UNIVERSITY: Yale scientists made an unusual discovery: The tree with 1,000 billion living beings VIDEO

A group of scientists from Yale University in the United States, who conducted a large study published in the prestigious journal Nature on August 6, 2025, made an amazing, completely out-of-the-ordinary discovery.

The scholars found that a single tree can host a trillion (1,000 billion) living things (microbes). The researchers took samples from 150 living trees of 16 species in the northeastern United States and found that these internal communities of microbes are not random.

A single living tree can host about a trillion microbes in its wood, with distinct communities in the inner and outer layers. This is not a rounding error - it forces a rethinking of what tree health and forest function really means, according to Earth. Jonathan Gewirtzman, a doctoral candidate at the Yale School of the Environment, led the study with the support of collaborators from several disciplines at Yale University in the United States.

Scientists have discovered that there are hidden worlds beneath the bark of trees. Most research on trees has focused on what we can see, such as leaves, roots, and bark. However, forests store vast amounts of carbon in living biomass, dead wood, litter, and soils, with global stocks estimated at about 861 gigatonnes of carbon in all reservoirs.

What happens inside wood is no footnote to the planet. The interior of the trunk is not uniform. The heartwood (the central part of the wood) is older, drier, and usually more insulated, while the sapwood is a younger tissue that moves water and nutrients upward.

The researchers extracted high-quality DNA from the woody tissues and profiled the bacteria and archaea in both layers to map who lives where. The team paired the genetic snapshots with measurements that indicate microbial activity in the wood, so this wasn’t just a catalog of dormant passengers.

Research that’s never been done before

These choices matter because a microbiome is more than a list. It’s a structured community whose metabolism can change the chemistry of its home. That’s exactly what the wood patterns suggest.

The inner wood favored anaerobic life that doesn’t require oxygen, a pattern previously seen in heartwood studies that reported methanogenic communities that thrive in low-oxygen conditions. The outer wood favored microbes that use oxygen, consistent with the sapwood’s role in water transport and exposure to air.

This separated the pathways by underlying physiology and chemistry. These communities include archaea alongside bacteria, and they do work that affects trees and ecosystems. This work includes biogeochemical processes related to gases and nutrients that, when scaled up across forests, can influence larger cycles.

“One of the things we found most interesting was how this microbiome varied across species,” said Wyatt Arnold, a chemical and environmental engineer and co-lead author of the study at Yale. “There’s a massive reservoir of unexplored biodiversity, countless microbial species living inside the world’s trees that we’ve never documented,” Gewirtzman said.

“We need to catalog and understand these communities before climate change alters them.”