Management of fire regime, fuels, and fire effects in southern California chaparral: lessons from the past and thoughts for the future

Chaparral is an intermediate fire-return interval (FRI) system, which typically bums with high-intensity crown fires. Although it covers only perhaps 10% of the state of California, and smaller areas in neighboring states, its importance in terms of fire management is disproportionately large, primarily because it occurs in the wildland-urban interface through much of its range. Historic fire regimes for chaparral are not well-documented, partly due to lack of dendrochronological information, but it appears that infrequent large fires with FR1 of 50-100+ years dominated. While there are concerns over effects of fire suppression on chaparral fire regimes, there is little evidence of changes in area burned per year or size of large fires over this century. There have been increases in ignitions and in the number of smaller fires, but these fires represent a very small proportion of the burned area. Fires in chaparral seem to have always burned the largest areas under severe fire weather conditions (major heat waves or high winds). Patterns of fuel development and evidence on the effectiveness of age-class boundaries at stopping fires suggest that, while fire in young stands is more amenable to control than that in older stands, chaparral of all ages will bum under severe conditions. We recommend a two-part strategy of: 1) establishment of strategically placed dynamic fuel management zones in wildland areas to provide access and opportunities for fire control, and; 2) intensive fire risk management zones (managed and developed cooperatively with local agencies and landowners) to protect values in the wildland-urban interface.