Bottom-up control of a northern Arizona ponderosa pine forest fire regime in a fragmented landscape
The authors investigated the relative influence of top-down climate controls versus bottom-up vegetation controls on the timing and spatial pattern of fire in a historically fragmented and patchy ponderosa pine landscape.
The study landscape was characterized by patches of ponderosa pine forest divided by a matrix of pinyon–juniper (PJ), sagebrush shrublands, and small grasslands. The authors did not find regional synchrony between the patches of ponderosa pine within the study area, suggesting that bottom-up controls, such as fuels, may have more strongly influenced the historical occurrence of fire in this region. The authors did find, however, as the scale of the analysis increased to larger regional areas, climate-driven fire synchrony increased, and fire was associated with dry condition in the year of the fire and wet conditions two years prior to the fire. The authors suggest that climate may be less influential on fire activity in ecosystems that are fuel limited.