Two tropical forests can store roughly the same amount of carbon while being built in fundamentally different ways. One may contain many relatively small trees. Another may contain fewer but much larger trees. Their trees may also differ in wood density and in how much of the forest is occupied by woody stems.

Look only at their total biomass, and those differences disappear.

That is the central insight behind a major new study published in Scientific Reports: “Region-specific forest structure pathways reveal climate effects on old-growth tropical forest biomass.”

Led by Pauline Depoortere with Jean-François Bastin and an extraordinary international team of 241 co-authors, the study brings together observations from 2,023 old-growth tropical forest plots across Central America, South America, Africa, Asia, and Oceania.

Its message is deceptively simple: to understand how climate influences the carbon stored in tropical forests, scientists need to look inside the forest—at its structure.

“To better understand how climate influences forest carbon stocks, we first need to understand how it acts on forest structure.”

— Pauline Depoortere

Looking beneath total biomass

Tropical forests are among the planet’s most important terrestrial carbon reservoirs. Yet scientists have long struggled to identify consistent relationships between climate and the amount of carbon stored in old-growth tropical forests.

The new study helps explain why.

Rather than treating aboveground biomass as a single response to climate, the researchers decomposed forests into four structural dimensions: basal area, mean tree diameter, stem density, and wood density.

The analysis shows that climate can influence these structural dimensions simultaneously—and sometimes in opposite directions.

For example, a climatic condition that favors more stems may also be associated with smaller average tree size. Another may favor larger trees but lower wood density. When these contrasting responses are added together as total biomass, their effects can partly cancel one another.

The result can look like a weak climate–carbon relationship even when climate is strongly associated with the underlying structure of the forest.

This is why, as Pauline explains, forests with similar carbon stocks can represent very different ecological systems.

The study also finds that these relationships are strongly region-specific. With the exception of wood density, which showed more consistent climatic responses, the ways in which forest structural attributes responded to climate differed across tropical regions.

That means there may be no single universal rule describing how tropical forest carbon responds to climate.

Instead, biogeographic history, species composition, and regional ecological strategies matter.

Five years behind one paper

The scientific result represents only one side of the story.

For Pauline, this publication marks the culmination of nearly five years of research—and her first paper as a researcher.

Before publication, she reflected on what lay behind the finished article:

“Almost five years of work, shaped by months in the field, sleepless nights coding, conferences, countless discussions, and collaborations with scientists from around the world.”

— Pauline Depoortere

Those collaborations ultimately grew into a scientific team spanning the tropical belt.

Jean-François Bastin, who worked closely with Pauline throughout the project, says one of the achievements he is most proud of is not simply the final analysis, but the way Pauline led such an unusually large scientific community.

“She managed to literally engage with all the co-authors on a very deep level.”

— Jean-François Bastin

That meant holding discussions across institutions, disciplines, continents, and time zones—and giving scientists responsible for different forest inventories meaningful opportunities to contribute to the interpretation of the work.

Bastin says Pauline repeatedly chose the more demanding path when it meant improving the science.

“She took all challenges as an opportunity to improve the manuscript and her knowledge as a young scientist.”

— Jean-François Bastin

The result is not simply a large-author paper. It is an example of how global ecological synthesis can be built through sustained scientific engagement.

The value of observations—and the people behind them

The 2,023 plots included in the final analysis were selected from nearly 20,000 candidate forest plots.

Behind every one of those observations are scientists, botanists, technicians, field assistants, institutions, and local partners who established plots, identified trees, measured stems, revisited forests, curated records, and maintained datasets—often over decades.

The study draws on contributions from several major forest research communities, including the Global Forest Biodiversity Initiative (GFBI), ForestPlots.net, RAINFOR, AfriTRON, and individual principal investigators.

Science-i served as an enabling and international coordination platform for the study, facilitating data access and project coordination and connecting participating researchers and data contributors through the GFBI community.

For Bastin, this infrastructure is inseparable from the scientific advance.

“This work is a beautiful contribution to our field, highlighting the value of field inventories [and] international collaborations.”

— Jean-François Bastin

The scale of the undertaking also required something less easily quantified.

“We needed a bit of creativity, passion, ambition and will to contribute, humbly, to our understanding of the planet.”

— Jean-François Bastin

And then came what is often underestimated in global collaborative science: patience and resilience.

Coordinating hundreds of scientists and multiple research networks is itself a substantial undertaking. Questions of data provenance, contributor recognition, interpretation, permissions, and authorship all have to be handled carefully if global data synthesis is to remain both scientifically rigorous and equitable.

For Bastin, the final publication therefore represents much more than an individual achievement. It is, in his words, “a substantial team effort.”

Why Science-i exists

For Science-i, this study demonstrates an important principle behind global scientific infrastructure.

Large-scale environmental questions increasingly require observations that no individual scientist, institution, or country could collect alone. But putting data in the same database is not enough.

Successful global science also requires trust, attribution, governance, communication, and mechanisms that allow the people who generated the observations to remain part of the science created from them.

That is the role Science-i seeks to enable.

“Global forest science depends on more than data. It depends on trust between the people who measure forests, the people who steward those observations, and the scientists who bring them together to answer new questions. Science-i exists to make that collaboration possible at global scale while keeping data contributors at the center of the scientific process.”

— Jingjing Liang, CSO of Science-i and co-author of the study

The new study illustrates that model in practice.

Science-i and GFBI contributed to a broader ecosystem of collaborating networks rather than replacing them. ForestPlots.net, RAINFOR, AfriTRON, GFBI, individual plot investigators, universities, research institutes, and hundreds of scientists collectively supplied different parts of the scientific foundation.

What made the pantropical analysis possible was the ability to connect them.

From a hidden climate signal to better forest science

The implications extend beyond explaining contemporary forest biomass.

If climate can alter different components of forest structure in different—and sometimes opposing—ways, models that predict future tropical forest carbon simply from climate and total biomass risk overlooking important ecological mechanisms.

A structure-explicit perspective provides a different path.

It asks not only whether a forest gains or loses biomass under a particular climate, but how the forest itself is organized: whether changes occur through tree numbers, tree size, wood density, basal area, or combinations of these attributes.

And because those pathways differ among continents, the findings reinforce another important lesson: tropical forests should not be treated as a single homogeneous system.

Understanding their futures will require both global synthesis and regional ecological knowledge.

That combination—global reach without erasing local and regional complexity—is also what international research networks make possible.

Congratulations to the global team

Science-i warmly congratulates Pauline Depoortere, Jean-François Bastin, and all 241 co-authors, together with the many field scientists, botanists, technicians, data contributors, institutions, and collaborators whose work made this study possible.

A special congratulations goes to Pauline for guiding a remarkably complex international collaboration through almost five years of analysis, discussion, revision, and publication—and for turning her first scientific paper into a genuinely pantropical effort.

The achievement belongs to an entire community.

And so does the knowledge it has created.

Read the study:
Depoortere, P., Bauman, D., Fayolle, A. et al. Region-specific forest structure pathways reveal climate effects on old-growth tropical forest biomass. Scientific Reports 16, 27381 (2026).
DOI: 10.1038/s41598-026-61888-7