Amazon forest fire history: policy brief summary
Radiocarbon dating of charcoal buried in the soils of intact Amazon forests shows that the most recent fire at each of three sites in Guyana and northern and southern Peru came 728 to 851 years ago, around 1200 AD. These forests have now gone longer without fire than at any time in the previous 2,000–3,500 years. Yet the carbon left by their past fires still makes up about a tenth of their soil carbon.
A new policy brief distils our Frontiers in Forests and Global Change study for fire management agencies, carbon standard bodies and researchers, and links it to what we know about the pyrogenic carbon that old fires leave in the soil.
Key findings
- The last fire was about 800 years ago: 33 radiocarbon dates on soil charcoal from three replicate pits at each of three intact terra-firme sites put the most recent fire at 728, 842 and 851 calibrated years before present.
- Fire was rare but recurrent: each site burned four to six times over 11,500 years, with median intervals between fires of 455 to 2,950 years.
- The legacy is still in the soil: about 11% of soil carbon to 2 m depth in intact forest is pyrogenic carbon, 2.8 billion tonnes in the top metre across the Amazon Basin (Koele et al. 2017).
- Today’s fires are a break with that history: MapBiomas Fogo mapped 690,000 km² burned across the Amazon biome between 1985 and 2020, 16% of its area (not all of it forest).
Recommendations
The brief makes three: treat any fire in intact forest as exceptional, with prevention of escaped burns and rapid suppression as the priority; credit pyrogenic carbon as durable, since carbon from fires centuries old is still in the soil; and date the last fire, using three soil pits per site, before calling a forest undisturbed.
Read the full policy brief below:
References
Feldpausch, T. R., Carvalho, L., Macario, K. D., Ascough, P. L., Flores, C. F., Honorio Coronado, E. N., Kalamandeen, M., Phillips, O. L., & Staff, R. A. (2022). Forest fire history in Amazonia inferred from intensive soil charcoal sampling and radiocarbon dating. Frontiers in Forests and Global Change, 5, 815438. https://doi.org/10.3389/ffgc.2022.815438
Koele, N., Bird, M., Haig, J., Marimon, B. H., Marimon, B. S., Phillips, O. L., de Oliveira, E. A., Quesada, C. A., & Feldpausch, T. R. (2017). Amazon Basin forest pyrogenic carbon stocks: first estimate of deep storage. Geoderma, 306, 237–243. https://doi.org/10.1016/j.geoderma.2017.07.029
Research supported by the Natural Environment Research Council (NE/N011570/1; NE/R017980/1) and the NERC-funded NEIF Radiocarbon Laboratory.
Header photo: © Paulo Brando. Understory fire in the southern Amazon.