What is defined as the area of unburned fuel located inside the fire perimeter?

The area of unburned fuel located inside the fire perimeter is referred to as an island. This term is used to describe patches of vegetation or other combustible materials that have not yet burned, even though they are surrounded by areas that have been affected by fire. Understanding the concept of islands is crucial for firefighting strategies, as they can serve as potential fuel sources for reignition or can be protected to help control the fire's spread.

Spot fires, which are small fires that ignite away from the main fire, refer to individual ignitions often caused by embers carried by the wind. Smoldering describes the phase of combustion where materials are burning slowly without flames, while crowning occurs when a fire transitions from the ground or surface level to the tree canopy. Each of these terms describes different fire behavior or phenomena but does not specifically indicate areas of unburned fuel within the fire perimeter. Thus, the identification of islands is important for effective fire management.