A new study reveals that the forests of the Canary Islands store 10.26 million tonnes of carbon, 25% more than previously estimated by the Ministry for Ecological Transition. This research, published in Carbon Balance and Management, introduces the first high-resolution map of forest carbon in the archipelago.
Covering approximately 112,735 hectares, these forests act as crucial buffers against climate change by absorbing carbon dioxide, the main greenhouse gas, and storing it in wood, branches, bark, and roots for long periods.
Conducted by scientists from the University of La Laguna and the Johann Wolfgang Goethe University in Germany, the study used advanced methodologies to produce detailed carbon maps. With a resolution of 50 metres, these maps allow detailed measurements of carbon in various forest types across the islands. Rüdiger Otto from the University of La Laguna noted that this level of detail is a significant achievement.
“The tool could be highly beneficial for sustainable forest management, ecosystem services, biodiversity conservation, and regional climate policy,” Otto said.
The findings indicate that La Palma has the largest carbon store, with 4.14 million tonnes, accounting for nearly 40% of the total. It is followed by Tenerife with 3.77 million tonnes and La Gomera at 1.28 million tonnes. Gran Canaria and El Hierro each hold around 0.5 million tonnes, representing roughly 5% each, while Lanzarote and Fuerteventura were excluded due to a lack of forest areas.
Canary pines constitute the majority of the carbon storage, holding 57.1% of the total, with 44.8% from natural forests and 12.3% from reforested areas. The evergreen forests, such as laurisilva, account for 37%, while exotic tree plantations contribute about 5%. Thermophilic forests have only 1.1% due to degradation from human activity.
The laurisilva, found mostly in Garajonay National Park, holds the highest carbon storage, with averages of 413.2 tonnes per hectare and peaks of 730 tonnes. This surpasses previous estimates and places laurisilva in La Gomera on par with tropical and subtropical rainy forests, thanks to favourable humidity conditions influenced by trade winds.
While the study provides a snapshot of carbon storage, it does not determine whether specific forests act as carbon sinks. Normally, forests absorb more CO2 than they release, but extreme heat and humidity globally are diminishing this capacity, raising concerns.
Otto pointed out that younger forests capture carbon more efficiently than older ones, despite having stored less over time. He emphasized the need for future research to track carbon stock changes over decades and identify which forests sequester carbon more effectively.
The study also highlights the critical role of water availability in plant growth and carbon accumulation, warning that rising temperatures due to climate change could increase evapotranspiration and reduce soil moisture.
Otto stressed the importance of protecting larger trees within the main forest types in the islands and assessing carbon storage to evaluate potential losses from land-use changes. Additionally, understanding these dynamics could enhance ecological restoration projects, especially on abandoned agricultural land, contributing to climate change mitigation.
