Tropical mountain forests store more carbon than expected
Tropical forests in Africa’s mountains store more carbon than previously thought. At the same time, vast amounts of the forests have already been lost. “This draws the attention to the importance of conserving these forests“, says Göran Wallin at the University of Gothenburg, co-author of the new study published in Nature.
Scientists studying tropical forests in Africa’s mountains were surprised to uncover how much carbon they store, and how fast some of these forests are being cleared.
The international study, reported in Nature, found that intact tropical mountain forests in Africa store around 150 tonnes of carbon per hectare. This means that keeping a hectare of forest standing saves carbon dioxide emissions equivalent to more than 4.5 million kilometers of driving – or 110 laps around the earth – with a new average petrol car*.
Carbon storage important for the climate
The study found that African mountain forests store more carbon per unit area than the Amazon rainforest and similar to lowland forests in Africa. Existing guidelines for African mountain forests – which assume 89 tonnes of carbon per hectare – greatly underestimate their role in global climate regulation.
“The article provides, for the first time, strong evidence that carbon storage in African mountain forests is significantly higher than previously thought. The results are surprising because these forests grow at high altitudes with lower temperatures, more clouds, higher wind speeds and steeper slopes compared to lowland forests”, says Göran Wallin, one of over hundred researchers who participated in the comprehensive study.
The forests are disappearing fast
The international team also investigated how much tropical mountain forest had been lost from the African continent in the past 20 years. They found that 0,8 million hectares have been lost, mostly in the Democratic Republic of the Congo, Uganda and Ethiopia, emitting over 450 million tonnes of carbon dioxide into the atmosphere. If current deforestation rates continue, a further 0.5 million hectares of these forests would be lost by 2030.
“About five percent of these forests have been cleared since 2000, and in some countries the deforestation exceeds 20 percent. Besides their importance for climate regulation, these forests have very high biodiversity, control erosion, and provide very important water services to millions of people downstream” says Göran Wallin.
“Historically, lowland forests have been more deforested due to agriculture expansion. Today, tropical mountain forests are seriously threated as well, for example by forest cutting, forest fires, mining and other human-induced disturbances,” he adds.
Deforestation must be avoided
According to the researchers of the study, better knowledge about how much carbon mountain forests store is especially important for the ten African nations where the only tropical forests they have are those found on mountains. In addition, they believe the results emphasize that although forest restoration is important to mitigate climate change, avoiding deforestation is a greater priority.
“We hope this study will contribute to better future conservation of these forests, for example by attracting funding through the carbon finance mechanisms”, says Göran Wallin.
Contact: Senior Lecturer in Environmental Sciences, at the University of Gothenburg, the Department of Biological & Environmental Sciences
Telephone: +46 705-82 11 55, +46 31-786 26 20
E-mail: goran.wallin@bioenv.gu.se
* Source: Transportstyrelsen, Transportstyrelsens statistik över koldioxidutsläpp från personbilstrafiken 2020
- A total of 101 researchers participated in the study: ”High aboveground carbon stock of African tropical montane forests”, published in Nature.
- Lead author is Dr Aida Cuni-Sanchez from the University of York.
- The researchers measured 72,000 trees in 44 mountain sites in 12 African countries.