Slow and steady tree growth wins the race for carbon capture

In the face of climate change, forests have become more than green landscapes. They regulate temperatures, purify air and water, protect soil, and support biodiversity.

Forests also absorb carbon dioxide from the atmosphere and store it in trees and soil, helping to reduce global warming.

Oceans do the same, but forests offer a land-based solution, one that we can manage directly. The idea of planting more trees has taken hold worldwide. But the story doesn’t end there.

Not all trees offer the same benefits. Some grow quickly, others slowly. Some survive tough climates, others do well only in ideal conditions.

The challenge for forest managers is figuring out which trees will trap the most carbon where they are planted.

The answer lies in matching tree traits with the land on which they grow.

A global study seeks answers

To explore this issue, researchers from INRAE and Bordeaux Sciences Agro teamed up with global partners. The project brought together the French National Forest Office (ONF) and the French National Center for Private Forest Ownership (CNPF).

Together, they studied 223 tree species in 160 forest sites around the world. These included locations in Western Europe, the United States, Brazil, Ethiopia, Cameroon, and South-East Asia.

Each species was chosen to represent one of the world’s major forest biomes. The team focused on functional traits – specific characteristics that affect how a tree grows, uses water and nutrients, and stores carbon.

Their goal was simple yet ambitious: to identify which traits lead to better growth and carbon capture in real-world forest conditions.

Old beliefs on carbon and trees

For a long time, scientists believed that trees with acquisitive traits grew the fastest. These trees absorb resources like sunlight, water, and soil nutrients very efficiently. In controlled experiments, such as those in greenhouses, they outperform other trees in height, leaf size, and biomass.

Examples include maples, poplars, English oaks, and sessile oaks. These species have large leaves and long roots that gather nutrients quickly. Their leaves also contain large amounts of nitrogen, which supports rapid photosynthesis. All these features make them ideal candidates for storing carbon – at least on paper.

On the other side are conservative species. These trees invest less energy in fast growth. Instead, they survive by conserving internal resources like water and energy. Fir trees, downy oaks, and holm oaks fit this model. They usually grow more slowly but are better at handling environmental stress.

A surprise from real forests

When the team took their research into real forests, their findings turned the old beliefs upside down. Under natural conditions in boreal and temperate zones, conservative tree species actually stored more carbon and grew faster than acquisitive ones. That may seem surprising, but the explanation lies in how these forests function.

Boreal and temperate forests often have cold climates, poor soil, or both. In such settings, being efficient with internal resources becomes more important than fast nutrient absorption.

In tropical forests, the story changes again. These regions have ideal growing conditions – warm temperatures and high rainfall. Here, acquisitive and conservative species grow at similar speeds. Neither group holds a strong advantage.

Matching trees with their environment

The biggest lesson from this research is that one size does not fit all. You cannot plant fast-growing trees everywhere and expect success. Tree performance depends heavily on local soil and climate conditions.

In rich, well-watered environments, acquisitive species like maples and poplars will outperform others. They can absorb nutrients quickly and convert them into biomass, storing more carbon. But in dry, cold, or nutrient-poor conditions, conservative species shine. Oaks, firs, and pines may grow more slowly, but they store more carbon over time because they survive and grow when others cannot.

The study highlights the need for precision in reforestation efforts. Forest managers must consider each site’s unique conditions. Planting the right tree in the right place is far more effective than planting the same fast-growers everywhere.

Choosing trees for better carbon impact

This new understanding gives forest managers a sharper tool in the fight against climate change. They can now look beyond growth speed and consider how a tree’s traits interact with its environment. This leads to smarter choices and healthier forests.

Climate action often demands quick results. But nature does not always work that way. Sometimes the slow-growing, stress-tolerant tree is the one that captures the most carbon in the long run.

With this knowledge, reforestation can become both more effective and more sustainable.

The study is published in the journal Nature.

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