Linking smallholder land use and fire activity: examining biomass burning in the Brazilian Lower Amazon

Abstract

Landscape forest flammability and regional biomass burning are critical environmental issues associated to fire use practices in the Brazilian Amazon. To better understand the gamut of these issues, all land use pathways that lead to fire use and culminate in different fire types must be investigated. An estimated 400,000 smallholders use fire in their land use practices, but most research has investigated connections between land use decisions and subsequent fire on large-scale cattle ranches only. This study presents research on smallholder fire use practices in the agricultural frontier south of Santarém, Pará. Vegetation vulnerable to smallholder fires is largely secondary succession, while only ∼8% is logged or mature forest cover. Fire efficiency in smallholder fire use practices is slightly higher than in previous studies used to estimate regional biomass burning, averaging 46.7–57.5%. In slashed succession areas, average efficiency also increases as biomass fuel load increases, but range increases as well, suggesting that smallholders may have more control over efficiency outcome in younger slashed succession areas than older slashed succession, logged areas or mature forests.