Fire Regime 3

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Mixed-hardwoods in the East and Midwest are Fire Regime 3. 

Credit: Brian Lockhart, USDA Forest Service, Bugwood.org

Fire Regime 3 occurs in somewhat cooler and wetter locations than Fire Regime 1, typically in the dry mixed-conifer forests of the West and mixed-hardwood/conifer forests in the East and Midwest.  Fires occur less often in this regime, so fuels have more time to build up.  These forests also tend to be more productive than their drier cousins, allowing fuels to build up more quickly and increasing the likelihood of a more severe fire. Fire typically burns through these forests without destroying them, but it can kill individuals or groups of trees as it burns through dense fuels.

Fire Regime 3 supports many different types of tree species, so fire behavior varies as it responds to the fuel characteristics of different vegetation. The dynamic nature of these forests means that trees can establish any time so forests tend to be all ages, including trees of great age.

Because fires are hot enough to kill trees, either individually or in groups, these forests tend to be very patchy, creating a “groupy-clumpy” structure, with grassy openings or meadows appearing here and there. Maintaining this patchy structure is important to the sustainability of these forests, as it is patchy fuels that keep the whole forest from being consumed when fire inevitably returns to these hot, dry locations.