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Bamboo-dominated forests comprise 1 % of the world’s forests. In southwest Amazon, a prior investigation mapped 16.15 million ha of bamboo-dominated forests by visual interpretation of Landsat and MODIS satellite images. They observed that the near infrared (NIR) wavelength was important to discriminate adult and dead bamboo areas, and estimated an average life cycle of 28 years for the Guadua spp. bamboo that dominate the region. In these bamboo areas, flowering and fruiting occur once in a lifetime before death, which produce massive quantities of necromass. The "bamboo-fire hypothesis" argues that increased dry fuel after die-off enhances fire probability, creating opportunities that favor bamboo. In this study, we developed and validated a method to map the bamboo die-off and its spatial distribution using satellite-derived time series of vegetation reflectance from MODIS (MAIAC) data and explored the fire hypothesis by evaluating the relationship between bamboo die-off and fires detected by MODIS thermal anomalies product in southwest Amazon. Our findings show that the NIR is the most sensitive spectral interval to characterize bamboo growth and cohort age. Automatic detection of historical bamboo die-off achieved an accuracy above 79 %. We mapped and estimated 15.5 million ha of bamboo-dominated forests in the region. The mean patch size during 2001–2017 die-off events was 85 km2, while the largest patch covered up to 6162 km2. The "bamboo-fire hypothesis" was not fully supported, because most bamboo cohorts did not burn after die-off. Nonetheless, fire occurrence was 45 % higher in dead than live bamboo in drought years, associated with ignition sources from land use, suggesting a bamboo-human-fire association. Since fire favors bamboo development, this may contribute to the maintenance of high bamboo density where it is already present, the expansion of bamboo into adjacent bamboo-free forests, or even bring deadly consequences to these adjacent forests under climate change effects. [ABSTRACT FROM AUTHOR]