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Wildfire Risk

Effects of Wildfire on Vegetation

Risk to vegetation will depend on the fire regime as well as the characteristics of the plants and trees exposed to a particular fire. The likelihood of a plant being killed by fire depends on a combination of time and temperature. High, sustained temperatures are most likely to result in plant mortality especially when several different parts of the plant have been injured. Trees are often able to survive as long as the fire does not spread into the canopy. Sometimes plants and trees survive the fire only to succumb later to disease, fungus or insects due to their decreased resistance caused by injuries sustained in the fire.

Streambank Afire

Streambank Afire (US Fish and Wildlife Service)

Many plants depend both directly and indirectly on regular burns in order to survive. Some trees, such as the lodgepole pine, have bark or cones that require heat from the fires to release their seeds and for seed germination. Fires can also kill diseases and insects that could otherwise destroy many plants. Other plants rely on fires to remove debris from the forest floor to reduce competition for growth and allow more access to light. The extra nutrients provided by the sun are essential for young trees trying to compete and for established trees to grow healthy and strong. Low intensity fires that clear away the underbrush also make it less likely that future fires will spread into the canopies of established trees, causing more serious damage.


Wildland Fire in Ecosystems: Effects of Fire on Flora.United States Department of Agriculture. Forest Service. Rocky Mountain Research Station. General Technical Report RMRS-GTR-42-volume 2, December 2000.