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Pattern and process of prescribed fires influence effectiveness at reducing wildfire severity in dry coniferous forests

Robert S. Arkle, David S. Pilliod, Justin L. Welty
Summary - what did the authors do and why?

This article examines the relationship between vegetation and topography on prescribed fire severity and the effects on subsequent wildfire.

Publication findings:

Prescribed fire reduced the severity of subsequent wildfire compared to untreated areas suggesting that prescribed fire is an effective treatment to reduce fuel loads and high severity fire in dry mixed conifer ecosystems. Pre-treatment vegetation volume, heat load, and prescribed fire burn severity were all significantly related to the severity of the subsequent wildfire; however, the interactions between these variables were complex. But, higher severities in the prescribed fire were more effective at reducing fire severity in the following wildfire.

The authors also found that landscape context of the burn strongly influenced wildfire severities. Fire severity was lower further inside contiguous patches of burned area and increased with increasing distance from the center of the disturbance. The authors suggest that fire size and burn continuity may be more important in reducing subsequent fire severity than the severity of the prescribed fire.

Fire and Ecosystem Effects Linkages

How do spatial and landscape patterns of fire relate to fuels?

The authors found that landscape context of the burn strongly influenced wildfire severities. Fire severity was lower further inside contiguous patches of burned area and increased with increasing distance from the center of the disturbance. The authors suggest that fire size and burn continuity may be more important in reducing subsequent fire severity than the severity of the prescribed fire.

How do annual area burned and fire size relate to fuels?

The authors suggest that fire size and burn continuity may be more important in reducing subsequent fire severity than the severity of the prescribed fire.

How does fire severity relate to fuels?

Prescribed fire reduced the severity of subsequent wildfire compared to untreated areas suggesting that prescribed fire is an effective treatment to reduce fuel loads and high severity fire in dry mixed conifer ecosystems. Pre-treatment vegetation volume, heat load, and prescribed fire burn severity were all significantly related to the severity of the subsequent wildfire; however, the interactions between these variables were complex. But, higher severities in the prescribed fire were more effective at reducing fire severity in the following wildfire.
The authors also found that landscape context of the burn strongly influenced wildfire severities. Fire severity was lower further inside contiguous patches of burned area and increased with increasing distance from the center of the disturbance. The authors suggest that fire size and burn continuity may be more important in reducing subsequent fire severity than the severity of the prescribed fire.