| Acreages within Fire Condition classes 1, 2, & 3 and Fire Regime classes I & II stratified by Inventoried Roadless Area category | |||||
| Fire condition class and fire regime data were only available for the lower 48 states. This table does not include acreages in | |||||
| Alaska or Puerto Rico. All acreage figures are rounded to the nearest 1,000. | |||||
| IRA Category | Fire Condition Class | Fire Regime | Acres | ||
| 1B | 1 | 0-35 yrs; Low Severity (I) | 524 | ||
| 1B | 1 | 0-35 yrs; Stand Replacement (II) | 141 | ||
| 1B | 2 | 0-35 yrs; Low Severity (I) | 1,453 | ||
| 1B | 2 | 0-35 yrs; Stand Replacement (II) | 375 | ||
| 1B | 3 | 0-35 yrs; Low Severity (I) | 1,218 | ||
| 1B | 3 | 0-35 yrs; Stand Replacement (II) | 5 | ||
| 1B-1 | 1 | 0-35 yrs; Low Severity (I) | 87 | ||
| 1B-1 | 1 | 0-35 yrs; Stand Replacement (II) | 4 | ||
| 1B-1 | 2 | 0-35 yrs; Low Severity (I) | 157 | ||
| 1B-1 | 2 | 0-35 yrs; Stand Replacement (II) | 41 | ||
| 1B-1 | 3 | 0-35 yrs; Low Severity (I) | 55 | ||
| 1B-1 | 3 | 0-35 yrs; Stand Replacement (II) | |||
| 1C | 1 | 0-35 yrs; Low Severity (I) | 1,579 | ||
| 1C | 1 | 0-35 yrs; Stand Replacement (II) | 674 | ||
| 1C | 2 | 0-35 yrs; Low Severity (I) | 4,341 | ||
| 1C | 2 | 0-35 yrs; Stand Replacement (II) | 453 | ||
| 1C | 3 | 0-35 yrs; Low Severity (I) | 2,400 | ||
| 1C | 3 | 0-35 yrs; Stand Replacement (II) | 37 | ||
| Definitions of Categories of Inventoried Roadless Areas | |||||
| 1B | Inventoried roadless area where road construction or reconstruction is not allowed | ||||
| 1B-1 | Inventoried roadless area where road construction or reconstruction is not allowed, and the forest plan recommends as wilderness | ||||
| 1C | Inventoried roadless area where road construction or reconstruction is allowed | ||||
| Definitions of Fire Condition Classes | |||||
| 1 | Forested areas with an historically short fire return interval usually have frequent fires of low intensity | ||||
| 2 | One or more fire return intervals have been missed, possibly resulting in increased fire sizes and intensities and decreased landscape mosaics and diversity | ||||
| 3 | Multiple fire return intervals have been missed resulting in dramatic departure from historical conditions | ||||
| Definitions of Fire Regimes | |||||
| 1 | 0-35+ years/low severity | ||||
| 2 | 0-35+ years/stand-replacement | ||||
| The Fire Regimes are described in terms of frequency and severity and represent pre-settlement, historical fire processes. Fire regimes I and II represent frequent fire return intervals. The 0-35+ years/low severity fire regime (I) occurs mostly on forested land. The 0-35+years/stand-replacement regime (II) occurs mostly on grasslands and shrublands. Fire regimes III, IV, and V have longer fire return intervals and occur on forest lands, shrublands, and grasslands. | |||||