Fuel Maps: Digitizing Grass and Sensing Fire in Brazil

Guilherme M. Fagundes, Princeton University §

Part and parcel of the technological repertoire in wildland fire management, fuel maps invite us to reflect on the everyday life of image production and analysis. I refer to these technologies as image-maps to draw attention to their dual function. As aesthetic objects composed of pixels, these images display vegetation characteristics that are imperceptible without technical mediations (Castro et al. 2020). Yet they are also maps that offer cartographic references to fire managers across different ecosystems around the world. In the Cerrado, a Brazilian savanna where I do research on fire techniques and politics in protected areas, fuel maps are changing how fire is used and how vegetation is perceived.

In this essay, I investigate how fuel maps offer a digital milieu for sensing fire by entangling local techniques and geotechnology. Fuel maps are addressed here with a focus on their usage, particularly when viewed in the field through smartphones. Based on my multimodal ethnography, I want to show how these image-maps configure an ecology of techniques by associating objects and actions with fire. My main objective is to investigate the coexistence of local techniques and geotechnologies in a world where savannas and forests are becoming digitized for managing environmental change (Gabrys 2020).

Figure 1: Projecting a fuel map on the wall. Photo by Guilherme Fagundes.

In January 2016 I was invited to participate in the annual zoning workshop of the Serra Geral do Tocantins Ecological Station (EESGT). I conduct research in this protected area of the Cerrado with environmental managers, firefighters, and Afro-descendant Quilombola communities since 2014. EESGT pioneered the Brazilian implementation of the integrated fire management (IFM), an environmental conservation program currently widespread in several countries and ecosystems. IFM has transformed the savanna’s ecological restoration. It recognized the role of burning practices in shaping the structure and composition of ecosystems that evolved with fire. Linking prescribed burns by park rangers to cultural burns by local communities, IFM seeks to incorporate non-Western knowledge within environmental management. Doing so also contributes to overcoming the militarization of wildfire suppression.

At this 2016 workshop, managers, Quilombolas, and other locals hired as firefighters met for three days to share perceptions on the behavior of fire in each ecosystem of EESGT protected areas. The group assessed the burns carried out during the first two years of IFM’s implementation. They then went to the field and ascertained the conditions of the vegetation to be managed through small burns. At the end of the workshop, they were able to establish the management zones based on what they began to call mapas de combustível (fuel maps).

Figure 2: Fuel map of EESGT, based on blue (exposed soil), green (photosynthetic vegetation), and red (dry or dead vegetation). Credit: Máximo Menezes.

What is a fuel map? Why does it change the ability to interact with fire? How do fuel maps mediate the relationship between local techniques and geotechnology? The answer to these questions involves gathering, storing, organizing spatially referenced satellite data, and converting it into images. Although I am unable to explore the entire process in this short text, I will focus on one of its aspects: the conversion of what is locally called cru (raw grass) into combustível (fuel). This conversion entails the ability to see and perceive the environment in its local signals. It is here that local knowledge of fire ecology becomes central to creating fuel maps. In order to map the fuel, it is first necessary to learn what fuel is locally—what really burns in local ecological conditions. In the Cerrado, Quilombolas and fire ecologists have their own techniques to inquire and respond to this question.

For fire ecologists, not all grass, wood, and vegetation is considered fuel because not all organic material reaches combustion in a wildfire event. Whether vegetation burns depends on the available combustible material, its calorific power, and the speed of flame propagation. Because these variables are related to specific ecosystems and seasonalities, the ecology of fire needs to be examined on the ground to produce data that can inform managers about these variables. In the Cerrado ecosystems where the EESGT is located, fire ecologists conducted fieldwork and established that fire consumes mainly plant biomass, dead or alive, with a diameter less than six millimeters and up to two meters from the soil surface. This definition of fuel includes the woody debris present in the soil, grasses, and herbaceous vegetation and that correspond to 94% of what is consumed by Cerrado fires (Miranda et al. 2002).

From the Quilombola communities’ perspective, the vegetation that actually burns is called cru. As they frequently say: “the food for fire is the cru.” As part of a pastoral and hunting lexicon, the word cru evokes a multispecies commensality related to fire and is literally translated as raw. This term is used in reference to dry grass at least two years old. After burning the cru, grass shoots feed both hunting animals (mainly emu and deer) and cattle raised in a transhumant and open pasture system called solta. This is why Quilombola herders and hunters are experts in perceiving the color and size that signal when the grass is cru. Their raising and hunting skills require detailed knowledge on the growth and aging of grass, informing the best moment to burn.

Although the words cru and combustível refer to the same combustible vegetable entity, they are associated with different cosmotechnical regimes (Hui 2017). Cru shows us how burning practices involve both Cerrado’s living beings and social institutions, their life forms and forms of life (Fagundes 2019). Herding livestock, hunting, and harvesting practices in the Cerrado trigger multispecies interactions mediated by fire that require burning at the right time. Placing themselves in an animal’s point of view, Quilombolas avoid carrying out fires that cause disease or collide with biological reproduction periods. Sensing the dryness of the grass, they are also experts in making the fire “run” through low-intensity preventive burns even at the end of the rainy season.

In contrast, the concept of combustível demonstrates how fire becomes part of a digital system for landscape management. When conservationist geotechnology converts cru into fuel maps, it does so through the energy reflected by the ground in the form of light and captured by satellite sensors. Each terrain emits signals that are captured in wavelengths of light based on the specificities of the exposed material. Pixels that compose such images are always a statistical average of the reflected spectrum. The image editor needs to employ field experience for this digitization since there will typically be a mixture of spectral information within each pixel for different strata of vegetation or exposed soil. The creative and situated quality of this process forces geotechnology to become local.

The fuel map in Figure 2 was one of the first created by my fieldwork host, the EESGT environmental manager Máximo Menezes, in the summer of 2016. On that occasion, he emailed me his map with the pride of an artist finishing a painting. Máximo spent hours of his working day using tutorials and open-source software to teach himself these techniques. He went through multiple stages of image correction, debugging code, adjusting fractions of what he called “mixed spectral responses” (intersections of green vegetation, raw grass, or soil). All of it was done manually to prepare the image. In Máximo’s map, the blue color is exposed soil, the green tone is forest and photosynthetic undergrowth, and the red tone is dry or dead vegetation. The intermediate colors suggest heterogeneous mixtures of dry vegetation and exposed soil (purple), green vegetation and exposed soil (turquoise blue), and dry and green vegetation (orange/yellow).

Figure 3: Photosynthetic vegetation, dry vegetation, and exposed soil. Photo by Guilherme Fagundes.

The person editing these images, such as my host Máximo, should be aware of what specific spectral response he intends to highlight. He is not simply identifying all types of vegetation. He seeks to map the specific types that can be burned—those identified as combustível or fuel. In the Cerrado where EESGT is located, the targeted spectral response in the mapping is what the locals call cru grass. This is the specific vegetation that burns the most and guides herders, hunters, and now also fire managers. Máximo’s craft demands a cultural and ecological translation to create a digital space for local fire managers. He must perform a visual conversion from cru to fuel maps compatible with the specific combustibility of native vegetation.

Rather than understanding Máximo’s work as a recording of real data, we should see it as a type of information conversion from one medium to another. To create a fuel map that works, my host must know the ecological and cultural conditions to translate his field experiences into digital media. It requires knowing how to convert the color variations of raw grass—a meaningful perception for the ranchers and hunters of the Cerrado who work as firefighters and fire managers—into color tones of an RGB (red, green, and blue) system that compose these image-maps.

I suggest addressing the digitization of grass fuel as a transductive operation (Helmreich 2017)—that is, a process of converting a form of energy through distinct media. This concept helps us focus on the conversion of grass into spectral signatures and then into shades of pixels that make up image-maps. To understand this process as a transduction means to look at it beyond an opposition between realism and constructivism, between capturing reality and representing it. Rather, it is a transformative communication that surpasses the simple recording of data and virtualization of reality.

Figure 4: Moving through fuel maps. Photo by Guilherme Fagundes. Edited by Pedro Branco.

This transduction chain mobilizes new devices in the field and establishes its own milieu. With the navigation app Avenza Maps, fire managers are able to explore Máximo’s digital fuel maps on their smartphones as a field guide. Avenza Maps can attach pictures of the burned ground directly from the field and measure the distance of the route or the area to be managed. One of its most relevant features is the geotracking ability to spatially locate users and track their routes in any area covered by the map without requiring an internet signal.

At the 2016 EESGT annual zoning workshop, Máximo used the fuel map projected on the wall to discuss the scars fire managers “touched up” with small doses of fire the month before. Then pointing at the burn scars with a laser pen, he said: “Look how beautiful this burn by João is! And this one by Deusimar, it’s surgical!” Recognizing oneself through images-maps demonstrates how the translation of cru into fuel is more than a simple abstraction of traditional ecological knowledge. It is true that the recognition of the landscape’s temporality through the spectral response of the vegetation delocalizes herding and hunting stories about burning areas. However, once introduced to the satellite language and able to read images on the RGB color system, Quilombolas and other local managers recognize themselves in the images by referring to their own burns. Stories of fire management acquire aesthetic traces and trigger artistic affiliations through a mosaic of scars on the landscape. When viewing image-maps, burned patches gain the status of authorship and strengthen even more their belonging to managed territories.

Digitizing grass also transforms patterns of wildland fire interaction. Fuel maps have the potential to anticipate the probability of ignition by creating horizons of responsive capacity (Petryna 2018). With the support of fuel maps, fire managers are expected to have more precision in their actions. How far will the fire go? What will the fire find? How long will the fire have to be active before reaching a given place? These questions used to be in the background for Quilombola herders and hunters, for whom fire is a medium for multispecies interaction. But with IFM, the cru became fuel and shifted to the foreground, from context to the object of the action. This transformation of cru into fuel doesn’t entirely hinder the coexistence of local burning techniques and fire management geotechnologies. While Quilombola communities’ burning practices are devoted to feeding animals and promoting herbs, the IFM focuses on the fuel itself. Although Quilombola and conservationist fires affect each other, their reasons for burning are based on divergent values and comprise distinct forms of living.

Figure 5: Touch-up preparation. Photo by Guilherme Fagundes.

This essay has sought to conceptualize the work of imaging nature beyond preconceived notions in an age of digital reproduction, such as the opposition between the real and the virtual. The transduction operation of fuel mapping does not alienate fire managers within a simulation that separates them from the environment and its dwellers. Treating the real and the virtual as antagonistic dimensions is a misconception of what the digital is (Vial 2019). If we are open to engaging with the modes of existence of these image-maps, we can overcome the anxieties that cloud our understandings on digital ecologies. Regarding the complementarity between technique and nature (Canguilhem 2000), without falling into technophilia or technophobia, fuel maps offer new channels of communication between local peoples and conservationists through an intercultural ecology of techniques.

Works Cited

Canguilhem, Georges. 2000 [1974]. “La question de l’écologie. La technique ou la vie,” Dialogue, mars 1974 (pp. 37-44). Annex to: Dagognet, François, Considérations sur l’idée de nature. Paris: Vrin, pp. 183-189.

Castro, Teresa, Perig Pitrou, and Marie Rebecchi, eds. 2020. Puissance du Végétal et Cinéma Animiste – La Vitalité Révélée par la Technique. Paris: Les Presses du Réel.

Fagundes, Guilherme Moura. 2019. “Fire Normativities: Environmental Conservation and Quilombola Forms of Life in the Brazilian Savanna.” VIBRANT (FLORIANÓPOLIS) 16: 1-22.

Gabrys, Jennifer. 2020. “Smart Forests and Data Practices: From the Internet of Trees to Planetary Governance.” Big Data & Society 7 (1): 1-10. https://doi.org/10.1177/2053951720904871

Helmreich, Stefan. 2017. “Transduction.” In: Keywords in Sound Studies: Towards a Conceptual Lexicon. David Novak and Matt Sakakeeny, eds. Pp. 222- 231. Durham, NC: Duke University Press.

Hui, Yuk. 2017. “On Cosmotechnics: For a Renewed Relation between Technology and Nature in the Anthropocene.” Techne: Research in Philosophy and Technology 21 (2): 1–23.

Petryna, Adriana. 2018. “Wildfires at the Edges of Science: Horizoning Work Amid Runaway Change.” Cultural Anthropology 33 (4): 570-595.

Vial, Stephane. 2019. Being and the Screen: How the Digital Changes Perception. Cambridge, MA: The MIT Press.

Guilherme M. Fagundes is an anthropologist of technique and life who researches intercultural fire management programs in fire-dependent ecosystems. His work explores the relationship between technodiversity and pyrodiversity through environmental conservation technologies, agro-pastoral systems, and multimodal ethnography. He is also a filmmaker and the director of the award-winning documentary film Other Fire. As a Postdoctoral Research Associate at Princeton University, he is currently playing a role in the new research and teaching initiative “Indigenous Ecologies of Knowledges across the Americas” (Brazil LAB/HMEI). He is also preparing his first book, “Making It Burn: Fire Techniques and the Government of Life in the Brazilian Savanna” for publication.

This post is part of our thematic series: Imaging Nature.