Fire Ecology in Southern California

Fire ecology is the study of the role of wildfire in the natural environment. While often viewed simply as a destructive force, fire is an intrinsic part of many ecosystems around the world that offers a variety of beneficial services including creating open habitats and controlling pests (Pausas, Keeley 2019).

In Southern California, fire has been part of our landscape for millions for years and has played an important role in shaping habitats and plant communities. Many California native plants have adapted strategies to survive fire and some even require elements such as heat, smoke, or charred wood in order to germinate. It’s estimated that more than 200 species are obligate seeders, meaning that they require post-fire conditions to germinate (Keeley 2017). The cycle of change brought on by fire is known as secondary ecological succession. Embracing this cycle, as part of the constant flux of our native ecosystems offers new ways of observing, appreciating, and connecting with California native plants.

Our Unique Fire Regime

A fire regime is a naturally occurring pattern of wildfire in a particular region. As a very large state, California has a variety of regimes. Northern California’s forested landscapes have historically experienced natural intervals of fire every 20 to 30 years. These are low intensity fires that burn across the surface of the forest floor below the tree canopy. In contrast, the natural interval of fire in Southern California’s shrublands is every 30 to 130 years (Keeley 2017). These are typically high intensity fires that burn plants down to the ground. Unfortunately, due to climate change and our growing population, we are experiencing a much higher frequency of wildfires in Southern California, and the vast majority of these fires are started by people. When fires burn too frequently, native plants do not have enough time to establish themselves and non-native, invasive plants take over. In Southern California, it’s difficult to find landscapes that have not burned in the past 50 years.


Up next: Post-fire Regeneration

Keeley, Jon. Postfire Ecology and What Urban Communities Can Learn About Adapting to Fire. Theodore Payne Foundation Fire Lecture Series, 2017, Sun Valley, CA

Pausas, Keeley 2019

This program was made possible in part by Edison International.

Illustrations by Edward Lum.