Why the Increasing Youth of Earth’s Tropical Forests Is a Surprising Climate Crisis

The mighty trees of ancient forests hold a vast amount of carbon in their trunks and branches. When these old trees are lost due to logging or wildfires, much of that stored carbon is released into the atmosphere.

Simon Besnard, a remote sensing expert, stated, “We’ve known for a long time that forest age is a key component of the carbon cycle. We wanted to quantify what happens when an old forest becomes young.”

A recent study published in Nature Ecology and Evolution looked into how forests aged between 2010 and 2020 and what this means for carbon levels.

Researchers created a global forest age dataset using information from over 40,000 forest inventory plots. They combined this with biomass and climate data to understand how forests have changed worldwide.

The results showed significant differences in forest aging across regions. Forests in Europe and North America have generally aged, while those in the Amazon and the Congo Basin have become younger over the past decade. Tropical forests, some of the world’s oldest, are seeing older trees replaced by younger ones.

Robin Chazdon, a tropical forest ecologist, noted that this trend carries important global implications, making it essential to understand where these changes are most pronounced.

Old forests, on average, store 77.8 tons of carbon per hectare, compared to just 23.8 tons in forests younger than 20 years. Interestingly, young forests can absorb carbon quickly but still can’t replace the carbon stock of older trees.

Besnard emphasizes, “When it comes to a forest as a carbon sink, the stock is more important than the sink factor.”

The study revealed that only 1% of forests transitioned from old to young, yet this small area contributed significantly to carbon loss—around 140 million tons out of 380 million tons.

Susan Cook-Patton from the Nature Conservancy pointed out that protecting forests is usually more effective for carbon, biodiversity, and cost than regrowing them after they’ve been damaged. However, restoring forests is also a vital solution for removing carbon from the atmosphere.

Understanding forest dynamics helps researchers manage forests better as part of climate solutions. But, Cook-Patton warns, “Forest-based solutions are not a substitute for fossil fuel emissions reductions.”

A critical gap exists in understanding what happens to carbon after trees are cut down. It can be stored in wood products or released by decomposition, depending on how the land is used afterward.

Besnard raised an important point about future research: “What is the fate of the biomass being removed?” Differentiating between natural, managed, and planted forests could also provide clearer insights.

Chazdon added, “Biodiversity issues are really paramount,” suggesting a need for future research to cover more than just carbon metrics. “A forest is more than that. It’s biodiversity, water, community—many things.”

For further reading on forest carbon dynamics, you can check out the article on EOS Magazine here.

Source link

carbon,Forests,trees