Geographic Variation in Mixed-Conifer Forest Fire Regimes in California

This paper reviews recent research from California on geographic variability in mixed conifer (MC) forest fire regimes. MC forests are typically described as having experienced primarily frequent, low to moderate severity burns prior to fire suppression that created a mosaic of vegetation patches with variable structure. Research throughout California generally supports this view, but recent research demonstrates that fire regimes and vegetation patterns in the MC zone were more complex and displayed significant spatial and temporal variability at landscape and regional scales. At the landscape scale, patterns of fire severity and fire return intervals varied with forest composition and environmental setting (e.g., fire frequency generally decreases from south to north facing slopes). There were also apparent regional differences in some fire regime parameters (e.g., season of burn, fire severity) and not in others (e.g., fire return interval). The degree of geographic variation in MC forest fire regimes suggests that researchers should be cautious when extrapolating relationships between fire regimes and forest structure that are observed in one area to other locations.