​An international team of scientists from universities in Europe and South Africa found that “Sacred Forests"* in Togo, West Africa play a vital role in the storage of carbon and could help to mitigate the effects of climate change. It is important to preserve the soil in these forests, which cover several hundred square kilometres, not just for carbon storage, but also for biodiversity and ecosystem functioning.

The findings of their study were published in the open-access journal Catena recently.

The researchers wanted to gain a better understanding of the variations in soil properties and the process of carbon formation in the soil under these highly biodiverse “Sacred Forests" which are used for religious purposes and believed to be inhabited and protected by gods, totem animals or ancestors.  They analysed the structure, components and features of the soil as well as the minerals that it contains.

“Our study showed that soils in these forests preserve at least 8.64 tonnes of inorganic carbon per hectare. This carbon is derived directly from the CO₂ in the air of the soil. In real terms, we are talking about an area the size of a rugby field that permanently removed as much CO₂ as is released by a power station burning 15.8 tonnes of coal," says one of the researchers Dr Michele Francis from the Department of Soil Science at Stellenbosch University. She conducted the study with Dr Hafeez Rehman (Norwegian University of Life Sciences, Norway), and Profs Rosa Poch (University of Lleida, Catalonia, Spain), and Fabio Scarciglia (University of Calabria, Italy).

Francis says “soil inorganic carbon is an important carbon sink because the carbon is permanently locked away in mineral form, unlike carbon derived from soil organic matter such as leaf litter and humus. The organic matter decomposes and releases the carbon back to the atmosphere as CO₂ again, unless there is a intermediary step which is able to capture and store the carbon permanently  ̶  as in the sacred forest soils.

She adds that due to the dry nature of the area, the mineral form of this inorganic carbon remains in the soil and does not dissolve. This will be an even more important form of carbon storage in the future, since the long-term trend is to an increasing severity of the aridity in Togo.

According to Francis, there is a high potential for development of the soils of the area in terms of agriculture and agroforestry and for potential carbon sequestration relevant to global change policies.

“Understanding these natural processes is fundamental for the implementation of soil management practices leading to carbon sequestration and improvement of soil quality status in the region, and possibly in other countries with similar climates, vegetation, and land use/land cover histories.

This is particularly important in areas where these forests are becoming rarer and more fragmented because of population growth, expansion of buildings, construction of roads, and erosion of traditional religious beliefs."

Francis adds that their findings would be of interest to people in agriculture, ecology, biology, forestry and earth sciences.

*The sacred forest is located in the Centre de Formation Rurale de Tami (CFRT), which trains local farmers. Much of the farming techniques rely on adding organic matter back to the depleted soils, for example by adding leaf litter, which mirrors the processes in the sacred forests. It is run by the La Salle brothers.

• SOURCE: Rehman, HU; Poch, RM; Scarciglia, F & Francis, ML 2020.  A carbon-sink in a sacred forest: Biologically-driven calcite formation in highly weathered soils in Northern Togo (West Africa). Catena: doi.org/10.1016/j.catena.2020.105027​