Our sites were located east of the Continental Divide in Glacier National Park, Montana (GNP) (Fig. 1). Two sites were located on Divide Mountain — Upper Divide and Lower Divide. Divide Mountain was treated as two sites because the two areas that A939572 burned at treeline differed in terms of the topography and the burned areas were separated by over 100 m of alpine tundra. The two sites were also the only areas on Divide Mountain that burned at treeline. The fire that affected Upper Divide appeared to have moved up from the western slope of the mountain, up the valley between Divide Mountain and Whitecalf Mountain; whereas the fire that reached treeline on Lower Divide appeared to have approached from the lower elevations on the northern slope of Divide Mountain. Upper Divide was located on a saddle (48° 39.5′ N, 113° 23.9′ W) at an elevation of 2200 m. The saddle is positioned with one slope facing east and the other facing west between Divide Mountain and the adjacent Whitecalf Mountain. Fine-scale topographic variations were also present on Upper Divide, and included a gully feature on the west-facing slope, steep slopes on both the west- and east-facing sides, and a more gentle sloping area near the top of the ridge. Sampling took place throughout the Upper Divide site. Lower Divide (48° 40.4′ N, 113° 23.6′ W) was located at a slightly lower elevation (2100 m) and was positioned on a north-facing slope. Most of Lower Divide was topographically uniform except for gradual change in elevation and a gully feature vasectomy extended up from the subalpine forest into treeline. Divide Mountain experienced a fire, the Red Eagle Fire, at treeline in 2006. The parent material is Altyn limestone (Resler, 2006). A third site was located on Swiftcurrent Mountain, where the Trapper Fire occurred in 2003. This site (48° 46.7′ N, 113° 46.1 W) was on a southward facing slope at elevations ranging from 2260 to 2340 m. The parent material is Grinnell argillite (Theodosis, 1955). Only one site was located on Swiftcurrent Mountain because fire only burned the sampled slope and the topography on that slope was uniform, except for change in elevation.