Supplement 1. Google Earth file (.kmz) with location of lakes used and referenced in this study (see Fig. 1 in main text), and polygons of recorded fires in Alaska from 1950 to 2007.

File List AK_tundraFireHx_LakeSedRecords_2008.kmz<br> AK_tundraFires_CAVM_2010.kmz Description Both files open in the program Google Earth and contain geographic data. AK_tundraFireHx_LakeSedRecords_2008.kmz: Location of high-resolution lake-sediment records reporting fire history information from Alaskan tundra, over the mid and late Holocene (DI, PE, RA, UC, PO, LI) and late Glacial and early Holocene (RP, XI). Records from the late Holocene representing boreal forest (RP, XI, CO, WK) are also included, because these are compared to tundra fire history records. Metadata include lake name, site code, year cored, surface area (ha), water depth (m), and publication information. AK_tundraFires_CAVM_2010.kmz: Polygons of tundra area burned in Alaska from 1950 to 2010, as reported by the Alaska Interagency Coordination Center (http://fire.ak.blm.gov/predsvcs/maps.php). “Tundra” is defined as all areas within the Circumpolar Arctic Vegetation Map (CAVM; Walker et al. 2005) in Alaska.