Just one percent of Amazon tree species account for half its carbon storage

The Amazon rainforest is home to around 16,000 different species of tree, but a recent study from the School of Geography indicates that just 1% of these tree species are responsible for storing almost half of the region's carbon.

“Trees produce sugars from CO₂, sunlight, and water through the process of photosynthesis, and some of these are eventually stored as wood. The Amazon forest helps us out by storing billions of tonnes of carbon that would otherwise remain in the atmosphere contributing to the greenhouse effect”, Dr Michelle Johnson, a co-author of the study, explained.

But understanding the carbon cycle of the Amazon, a vast and diverse ecosystem, presents a huge challenge. To tackle this, the RAINFOR network, made up of South American and European researchers was established. In the latest study, RAINFOR scientists used data from over 500 forest plots and 200, 000 trees to compare the abundance, biomass stock and woody growth of each species.

Lead author Dr Sophie Fauset said, “Certain species are already recognized as being especially abundant in the Amazon, but it was unknown whether these actually dominate the forest carbon cycle. We found that while species that are very common often do store a lot of biomass, others store or grow much more than their abundance suggests.”

One particularly important species is Bertholletia excelsa, known for producing Brazil nuts (left), which ranks third in terms of carbon storage, despite making up fewer than 0.1% the trees in the Amazon.

The knowledge that only a small fraction of tree species are responsible for processing and storing half of the region’s carbon could help scientists predict how rainforests will cope with future climatic changes. However, overlooking the other 99% of species could be dangerous, as Professor Oliver Phillips, co-author of the study, explains, “Our team has worked out which plants ‘matter’ most right now. But, as the Amazon climate continues to change, we may expect a very different set of trees coming to the fore, including some barely noticed now.”

Find out more about RAINFOR here, or read the full study here.

Post by Cat Scott - University of Leeds.