Carbon farming in the desert proved possible – best results with eucalyptus
The energy company St1 carried out an afforestation experiment on an arid zone in Morocco to create carbon sinks. New vegetation cover also helped improve the conditions of local population.
What was just an expanse of sand and rocks in 2018, was by 2022 a small, green forest. The project was one of many similar ones in different parts of the world, with the aim of starting carbon farming in arid zones and thus helping to curb climate change. Research has shown that young forests in rapid growth are effective binders of carbon, that is, carbon sinks.
In this pilot project by the energy company St1, seven different tree species were planted in the arid zone in Benguerir. The ones found to work best in carbon sequestering were eucalyptus, moringa and carob.
Speaking in connection with the publication of the pilot project results in May, Mika Anttonen, Chair of the Board of the Finnish company St1 Nordic, said that climate policy and climate action must always include a global perspective. He pointed out that the world’s population and economies continue to grow, while the amount of biomass in the world is shrinking. Climate experts have concluded that the area of new forest required is equal in size to Sahara.
’Sadly, the amount of carbon is increasing continuously and rapidly. The best and most sustainable way to curb that is by means of plant photosynthesis,’ Anttonen said.
Anttonen believes that voluntary action is insufficient to bring about a decrease in atmospheric carbon.
’In addition to obligating us, the sellers of fossil energy, to bring various non-fossil products to the energy segment, we should also be obligated by law to bind carbon.’
Involving locals in cultivation
The body in charge of the field experiments in the St1 pilot was Natural Resources Institute Finland. The experiments were conducted in collaboration with the local Mohammed VI Polytechnic University. According to Mohamed Louay Metougui, PhD scientist in Agroforestry and Rehabilitation, it is particularly important to engage local people in the cultivation project.
’Quite a number of people were doubtful: why should you plant a forest instead of something you could eat?’ Metougui said.
However, the pilot project also succeeded in responding to the needs of the local population. The results show the many advantages of ecological agroforestry.
Agroforestry uses the same field to grow annual crops and trees. The pilot area in Morocco was suitable for carob and moringa to sequester carbon, and between the rows of trees, quinoa and fava bean were planted for food. The eucalypti provided a wind screen for other plants.
Irrigation needed for growth
The hot, arid pilot area in Morocco has an average temperature of 37 degrees Celsius in the summer, and 19 degrees in winter. The annual rainfall is 250 millimetres.
This is why the most important findings from the afforestation trial are related to irrigation. Even a small amount of sub-surface drip irrigation improved the rate of survival of the trees. On a small special plot, groundwater was used for irrigation. However, the final report notes that the most sustainable irrigation option for larger areas is desalinated sea water.
The size of the experimental area in Morocco was just under four hectares, and the number of seedlings planted there was somewhat over 5,000. The cost of one metric ton of sequestered carbon came to EUR 97, which includes the cost of the irrigation system.
Despite the comparatively high price per sequestered carbon ton and the small size of the trial plot, the researchers consider that significant carbon sinks may be created in the future by afforesting arid zones.
’In terms of carbon sequestering, all carbon sequestered here was additional. In other words, it would not have been sequestered naturally over time,’ Anniina Lampinen from St1 said to forest.fi earlier.
