Understanding fire terminology is critical to understanding the role of fires within the environment. Historically, crown fires, as well as ground fires, occurred throughout the west. However, crown fires (movement of fire through the tops of trees and shrubs and independent of the surface fire) were less common because of periodic, small ground fires (fires that move along the bottom of the forest and remove surface fuels such as grass, leaves, plants, shrubs and trees, but leave some vegetation intact).

No matter the type, fire is going to occur. It’s just a matter of which type. Today, following almost one-hundred years of fire suppression efforts, crown fires are more likely to occur than ever before. Sometimes a crown fire can be so hot, and move so quickly, that it can destroy an entire vegetation community, which many times cannot be replaced. Ladder fuels (downed live and dead wood that provides a continuity between the forest floor and the canopy crown) increase the likelihood of a high intensity crown replacement fire.

Ground fires, which were probably once a vital part of western forests, typically burn at low intensity, and create smaller, mixed patches of burned and unburned vegetation. Fire managers today recognize prescribed burning as a tool to help simulate historic ground fires.

Prescribed burns are used to alleviate crown fires, remove ladder fuels and are an essential tool in managing ecosystem health. Most forests have a Fire Management Plan and schedule and conduct such fires according to specific “prescriptions.” These criteria may include economical, environmental and geographical considerations, as well as, social, legal and safety requirements.

For more information you can download the Adobe Acrobat file Glossary of Wildland Fire Terminology (1.5M)

Prescribed fires are typically ground fires, carefully managed by trained resource personnel.