Amidst a summer marked by devastating fires and heat records, the forests of the Canary Islands offer positive news regarding climate change. A recent study published in the journal Carbon Balance and Management estimates that the archipelago's forest masses, covering approximately 112,735 hectares, store 10.26 million tons of carbon. This figure is 25% higher than previously calculated by the Ministry for Ecological Transition (MITECO) in its 2020 forest inventory.
Forests are a fundamental defense against global warming. Through photosynthesis, they absorb carbon dioxide (CO2) from the atmosphere, release oxygen, and retain carbon in their wood, branches, bark, and roots for decades or centuries. The novelty of this research, involving scientists from the University of La Laguna (ULL), the Johann Wolfgang Goethe University (Germany), and the Spanish National Research Council (CSIC), lies in its methodology. They have generated high-resolution maps (50x50 meters) that allow for the quantification of stored carbon in any forest type and at any point in the Canary Islands.
“"This tool could be very useful for sustainable forest management, ecosystem services, biodiversity conservation, and regional climate policy."
The results indicate that La Palma holds the largest carbon store in the archipelago (4.14 million tons, nearly 40%), followed by Tenerife (37.5%) and La Gomera (12.4%). Gran Canaria and El Hierro each store around 5%. Lanzarote and Fuerteventura were excluded due to the absence of significant forest masses.
Canary pine forests are the primary carbon storage areas (57.1%), followed by evergreen forests like laurisilva and monteverde (37%). Plantations of exotic species (radiata pine, eucalyptus) account for about 5%, and thermophilic forests, due to degradation, only 1.1%. The laurisilva stands out as the ecosystem storing the most carbon, particularly in the Garajonay National Park on La Gomera, with levels comparable to tropical forests.
The study provides a snapshot of stored carbon but does not specify if a particular forest is actively acting as a carbon sink. While forests normally offset emissions, extreme heat and high humidity can diminish this capacity globally, accelerating decomposition and releasing CO2. Younger forests tend to capture carbon more rapidly than mature ones, although the latter have accumulated more over time.
Researcher Rüdiger Otto highlights water as a limiting resource and warns that rising temperatures may increase evapotranspiration, reducing soil water availability and affecting vegetation growth and carbon capture capacity. He proposes protecting forest masses with larger trees and quantifying stored carbon to estimate losses from land-use changes, such as infrastructure development. This would also help identify carbon sequestration potential in areas at different ecological succession stages, aiding restoration projects.
