The Reintroduction of Fire in the Irish Hills of San Luis Obispo County
The Irish Hills of San Luis Obispo County contain about 60,000 acres of sparsely populated, heavily vegetated, forest and ranch land owned by both private and public entities. The area is designated as State Responsibility Area by the CAL FIRE-Fire and Resource Assessment Program. The Irish Hills are situated between the Pacific Ocean, Avila Beach, Los Osos and San Luis Obispo. The topography is very broken, rising from sea level to 1400 to 1600 foot peaks within one mile of the shore line. The local Mediterranean climate, typical to many coastal areas of California, dominates the Irish Hills with morning fog, afternoon sun and daily sea breezes.
The Irish Hills have gone through many changes over the years. The Chumash and Salinan Native Americans once lived there in large villages, gathering food from the ocean and rich forest lands that the Irish Hills area provided. It is believed that Native Americans regularly conducted vegetation burns to clear away dense brush and promote new growth. Locals claim that the Spaniards originally named the area Montana De Oro, or Hills of Gold, because of the California Poppies that grew on the hill sides after the seasonal burns. Soon after the Spaniards and Americans settled in the area, most vegetation burning was ceased. In the last 100 years, Irish Hills residents have included ranchers, potato and hay farmers, miners, and several developers looking to capitalize on the many natural hot springs found in the Irish Hills.
Irish Hills fire history maps, administered by the California Department of Forestry and Fire Protection (CAL FIRE), CAL FIRE –San Luis Obispo Unit, indicate very little fire history in the last 60 years. The few fires that are recorded burned very intensely in thick and decadent vegetation and proved very hard to contain due to limited topographical features that favor suppression actions.
In January 2007 during a prolonged period of dry weather and North Winds, a structure fire ignited the Diablo Fire, just north of the Diablo Canyon Power Plant. Before it was contained, the Diablo Fire burned about 300 acres of brush and Bishop pine forest. After the Diablo Fire was contained, CAL FIRE, California Department of Parks and Recreation (DPR) and the Pacific Gas and Electric Company (PG&E) met to discuss using the Diablo Fire perimeter as an anchor point to reintroduce fire into the Irish Hills. A series of prescribed burns under CAL FIRE’s Vegetation Management Program (VMP) were planned with the following objectives:
1. Improve wildlife habitat
2. Regenerate large stands of diseased, dying and dead Bishop pine forests which are serotinous pines of the California-Baja California coast and require intense heat for reproduction.
3. Temporarily improve cattle and goat grazing conditions.
4. Reduce wildland fuels to maintain system reliability of the Diablo Canyon Power Plant and related facilities
The impact of fire on different plant communities varies, but within days of the Diablo Fire and each successive prescribed burn, new green leaves appeared at the base of burned Coyote brush and California sage. Along with native grasses, many other plants have reestablished themselves throughout the burns. Many Irish Hills native plants have special adaptations to fire and actually require fire for continued reproductive success and to maintain a healthy plant community. The Bishop pine is a perfect example as it requires heat to melt the resin in the cones to release seeds, and prefers bare mineral soil with plenty of sunlight for seedling survival. 
Sticky Phacelia, a Wild Flower that Emerges After a Fire
CAL FIRE will continue to work with landowners and stakeholders to build upon the recent success of the VMP program in the Irish Hills area. Projects of varying size and scope will be planned and implemented to further utilize the VMP program and demonstrate proper land management techniques. Currently, plans are being prepared for several studies to be developed and undertaken by DPR and PG&E using their own employees as well as students from California Polytechnic State University, San Luis Obispo.
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