Whitlock concentrates on the material that is found in lakes, extracting sediment cores that contain the fossils of pollen and particulate charcoal. Pollen grains can provide information about the plants that lived in the lake, meaning Whitlock can work out the vegetation and climate. By studying the charcoal in the sediments, Whitlock can track past fire. She has analysed the sediment cores in both wetlands and natural lakes. She uses the information she can extract from sediment cores to reconstruct historical vegetation, fire and climate. After the Yellowstone fires of 1988, Whitlock developed tools to reconstruct previous fires using the charcoal particulates contained within lake sediments. She monitored the lakes that were close to the Yellowstone fires for ten years, studying the amount of charcoal in small lakes in burned and unburned waterbeds. She studied the origins and amount of charcoal in these lakes and established the way that charcoal had been transported from the lake to the sediment cores she extracted. She compared the charcoal abundance during the 1988 fires to historical fires at the Yellowstone National Park. The methods she developed are still being used by fire scientists in a Global Charcoal Database.