Biochar for carbon capture in forests

Biochar is produced by pyrolysis — combustion at high temperatures without an oxygen supply. Different types of biomass, such as wood chips or straw, are combusted, resulting in a product similar to barbecue charcoal. Biochar is resistant to decomposition. It can be used for soil amendment and to improve carbon capture in soils, but also as a fertilizer, especially if it is enriched with nitrogen.

While Norwegian agricultural land make up approximately 1.1 million hectares, or around 3% of the land area, the forests in Norway cover over 12 million hectares, or 37% of the country's land area. Forests also play a very important role in Norway's greenhouse gas accounting, and this is where biochar comes in.

Different methods for long-term carbon capture and storage in soil and forest, also known as Bio-CCS (Carbon Capture and Storage), are essential in our fight to stabilize, or ideally reduce, CO₂ emissions. To achieve the target in the Paris Agreement of limiting the global warming to max 1.5–2°C within the next 80 years, it is essential to utilize trees' photosynthesis and the tremendous capacity of forest soil to capture and store CO₂.

Studies have shown that biochar can increase growth in agricultural crops by 10 - 25%. In pot experiments with tree seedlings, the average growth increase was over 40%. During the four-year FORBIOCHAR research project, the effect of standard forestry fertilizer will be compared with that of biochar, and biochar enriched with fertilizer.

"In theory, the nitrogen-enriched biochar could have a triple effect, with increased growth, increased carbon storage and less runoff," explains NIBIO researcher Kjersti Holt Hanssen.