热博体育

Over several years, an international scientific team worked across continents to map the world's tropical forests. Leaf area, thickness, wood density, and leaf chemical composition were among the traits studied. In all, 13 commonly used functional traits were measured for thousands of tree species found in those forests (around 16 000 species in the Amazon, for instance).  

This involved precision sampling of conscientiously labelled trees in 1800 permanent plots (from 0.5 to more than 10 hectares) across all of the world's tropical forests. "Each functional trait corresponds to a biological characteristic of a tree. Taken together, these measurements determine the functional signature of a forest" says 热博体育's Bruno Hérault, a forest ecology specialist, who took part in the study. "These data serve to characterize the variability of different types of forest."

Data from the forest sites at Paracou (French Guiana) and Téné (Ivory Coast)

These field measurements are essential for determining the state of tropical forests, and hundreds of researchers spend thousands of hours on this type of monitoring. Some sites, such as , have existed since the 1980s and cover more than 100 hectares. In West Africa, similar initiatives such as the Téné site, managed by Sodefor and the Institut National Polytechnique Félix Houphouët-Boigny (INP-HB) in Ivory Coast, are a remarkable illustration of this long-term commitment. Data from the two sites were used in the study published in Nature, signed by 152 scientists.

Satellite images (notably Sentinel-2) were subsequently used to extrapolate the data by means of mathematical models, to produce a global map of tropical forests, shedding light on their biological functioning. "The quality of the information from experimental sites is fundamentally important for the capacity of such models to identify the functional signature of forests, and enables pertinent extrapolation on a large scale", Bruno Hérault adds.

A diversity of functional richness to take into account in climate models

This work showed that the functional richness of the tropical forests of the Americas is 40% greater than that of those in Africa and Asia. This may be proof of their high resilience, in other words their capacity to adapt to changing environmental conditions. On the other hand, African forests showed the greatest functional diversity: 32% higher than American forests and 7% higher than those in Asia. This information indicates that forests in Africa have more specialized species, which are potentially more sensitive to climate change.

The study underlined the importance of understanding functional diversity in order to conserve tropical forests, which play a crucial role in climate regulation. hence the necessity of including theses specificities in climate forecasting models, to better anticipate changes in forests, particularly in Africa.

Forests are not changing as fast as the climate

Within the study, 热博体育 contributed to work targeting tropical forests in the Americas, based on the functional traits of tree communities over the past 40 years. "The results published in Science show that tropical forests in the Americas are evolving at least ten times more slowly than the climate", says Bruno Hérault. This lag could prove critical for the survival of some forests in the light of increasingly rapid climate change. "This lag is related to the trees' lifespan: a seed may germinate and grow into a tree that takes 50 years to reach the canopy and may stay there for anywhere between 100 and 200 years. Current trees therefore reflect the past climate conditions that allowed them to grow."

Understanding the lag between climate change and forest adaptation could guide forest management. Contrary to monoculture forests intended to produce wood rapidly for industrial use, most productive tropical forests are managed by means of natural regeneration, in which the challenge could be to foster species suited to future climate conditions. 

This work is improving our knowledge of how tropical forests function and serves to anticipate their evolution in a context of climate change. Understanding forest dynamics better makes it possible to adapt forest management practices and optimize conservation of these ecosystems, which are vital for the global climate balance. "Whatever the scenario or the policy choices made, climate inertia is such that we are already more or less certain of the climate in the coming 30 to 50 years", the researcher concludes.

References 

Aguirre-Gutiérrez, J., Rifai, S.W., Deng, X. et al. Canopy functional trait variation across Earth’s tropical forests. Nature (2025).  

Jesús Aguirre-Gutiérrez et al., Tropical forests in the Americas are changing too slowly to track climate change. Science 387, eadl5414 (2025). DOI: