I am a first-year PhD student at Wageningen University. My PhD research focuses on forest-savanna transitions in the tropics. Recent work has provided evidence that tropical forest and savanna can be alternative stable states under a range of climatic conditions. One mechanism thought to be responsible for this is a feedback between savanna grasses and fire. These fires, like herbivores, may keep the savanna landscape open while high canopy cover (forest) suppresses fire under the same climatic conditions. Such self-stabilising feedbacks enable critical transitions, or tipping points, between alternative ecosystem states. In this case, one can imagine that climate change would cause a fire-mediated transition to savanna in parts of the Amazon rainforest. I try to understand the above dynamics using simple ecological models and remote sensing data.