From: Characterizing persistent unburned islands within the Inland Northwest USA
Fire regime | Frequency | Â | Â | Example cover type from |
---|---|---|---|---|
group | (yr) | Severity | Severity description | study area |
I | 0 to 35 | Low or mixed | Generally low-severity fires replacing less than 25% of the dominant overstory vegetation; can include mixed-severity fires that replace up to 75% of the overstory (typical of perennial grasslands) | Ponderosa pine; dry mixed conifer forest |
II | 0 to 35 | Replacement | High-severity fires replacing greater than 5% of the dominant overstory vegetation (annual grasslands and some forests with frequent surface fires) | Grassland |
III | 35 to 200 | Mixed or low | Generally mixed severity; can also include low-severity fires (many forests and shrublands) | Big sagebrusha, lodgepole pineb |
IV | 35 to 200 | Replacement | High-severity fires (forests and shrublands) | Big sagebrush, lodgepole pine |
V | ≥200 | Replacement or any severity | Generally, replacement severity; can include any severity type in this frequency range (some moist forests, tundra, and deserts) | Very sparse big sagebrush steppe; spruce–fir forest |