FAPESP - Amazon PyroCarbon: Quantifying soil carbon responses to fire and climate change

Lead Research Organisation: University of Exeter
Department Name: Geography


Wildfires are becoming the new normal across Amazonia. Deforestation is transforming the region at a rate of around 10,000 square km/year (half the area of Wales), and now the area degraded annually -forest logged and burned but not cut down-is greater than the area deforested. Fire has historically been rare in Amazonia, meaning that the forests are not adapted to fire and the trees often die from fires - releasing carbon (C) back to the atmosphere and amplifying global climate change. Burning of tropical forests is already releasing more climate-warming carbon dioxide than fossil fuel burning in the whole of Europe. Trees in Amazonia contain around 7x more C than humans are releasing every year, and soils contain the same amount again, so it is vital to understand what is happening to this C and minimize emissions.

As vegetation sheds its leaves, branches, and roots, or dies, some of the C released remains in the soil, and some is later decomposed and released back to the atmosphere. Carbon exists in the soil in many different forms, from new inputs from decomposing plant material to ancient C formed over millennia. Burning adds pyrogenic carbon (PyC) to the soil, a partially burnt form of C that is resistant to decomposition and could make the soil more fertile. Because soil C takes a long time to form, its conservation is particularly important.

Despite the widespread increase in fire in Amazonia, there have been few measurements of soil C fractions and dynamics in burned areas - most have focussed on natural forests. Burned forests will have different composition, forest structure, and C dynamics. Understanding how different soil C fractions are formed and lost is crucial to understand how fire and climate change affect C storage.

We propose to make major advances in understanding fire impacts, including the processes that affect the type and quantifies of soil C formed, and how C gains/losses vary over time, with soil type, and climate. We will combine new measurements with innovative modelling to inform land management strategies and C budgets.

We have already collected data from across Amazonia in intact forests that have not recently burned. Crucially our project will collect a new, comprehensive dataset from human-modified forests, including logged, burned and abandoned land. We will use an approach known as a chronosequence, where we take samples at sites that were burnt at different times in the past, so we can see how the soil C has changed after e.g. 1 year, 2 years, or up to 20 years after a fire. This will then be used to develop a state-of-the-art land surface model, JULES, which forms part of the UK Earth System Model.

At our sample sites, we will evaluate how different burn severities affect soil C, both in surface and deep soils, and how these change over time post-burning and with soil, climate, and land-use such as logging. At 3 focal sites, we will take detailed measurements of the decomposition rate of the C over 4 years, comparing measurements with different land-use, burn severity and wet vs dry seasons. Knowing what forms C takes after a fire and how fast it decomposes under different conditions will enable us to build these processes into the JULES model. We will model PyC globally for the first time and make projections of land C changes in Amazonia over the next ~40-60 years under different management practices.

As well as transforming scientific understanding of post-fire soil C and its resilience to climate and management, our project will inform socio-environmental planning for sustainable resource use to conserve soil C. We will work with regional partners, fire managers, state and national policymakers to integrate our findings into decision-making to minimise negative fire impacts. Due to the Amazon Basin-scale of our work, these strategies are a crucial step to limit the risk of large-scale loss of soil C.


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Vedovato L (2023) Ancient fires enhance Amazon forest drought resistance in Frontiers in Forests and Global Change

Description Teach the teacher: developing local capacity to teach about forest fires risks and impacts and alternative land-use in Mato Grosso, Amazonia, Brazil 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Our approach, based on the concept of "teach the teacher", will work with local partners to train local secondary education teachers about the effect of fire on forests and alternative land-use practices in Mato Grosso, Amazonia. The teachers will then use the new training and teaching material we provide to teach their students in new ways and on new topics about fire and alterative land-use in Amazonia.

1) Identify teaching needs and develop outreach material:
First, meet with local secondary education teachers and learn from them which specific themes about fire in their region would be most beneficial to develop teaching material, e.g., burning impacts on air quality, water availability, or biodiversity.
Develop outreach and educational material, building on material about fire produced by our project in collaboration with local partners, including a book (Fogo!), infographics, and cartoon drawings for children. Make the material available on a project website for future use by teachers.

2) Teach the teacher:
Work with local research partners to train local university students in secondary education programmes about fire and alternative land-use based on findings from our NERC-supported research across Amazonia, doing this in Mato Grosso, Amazonia heavily affected by fire: Mato Grosso State University via a PhD student at UNEMAT, Brazil supervised by PI Feldpausch, and on leave from his post as a secondary education teacher, with a requirement by his state school to produce teaching material.

3) Local school outreach:
With local partners, develop the capacity of local secondary education teachers to teach about fire. We ran a three-day workshop and training session with local teachers. We will produce a short film about the teachers' experiences and publicise the work through social media and a web page. Feedback from the teachers will be used to improve online teaching material.
Year(s) Of Engagement Activity 2022,2023
Description Training for post-graduate students in Brazil 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Profs. Ted Feldpausch, Plinio Camargo, and Dr Lidiany Carvalho led the training of post-graduate students from UNEMAT, Brazil and CENA, Brazil in field research methods for soil analysis and vegetation sampling in Mato Grosso, Brazil.
Year(s) Of Engagement Activity 2022