We studied the effects of a shift in the fire regime of an ecosystem that is very sensitive to climate change: the ecotone from closed forest to open alpine tundra, hereafter the alpine treeline ecotone (ATE). Results suggest that ATEs will become more complex spatially in a warming climate, rather than moving up or down en masse. Management of these areas, many of which are in protected areas (wilderness and national parks), will continue to be adaptive, anticipating landscapes of the future that will change in complex ways and differently in different ecoregions.