There is no denying that the scale and intensity of California wildfires is increasing. According to the National Interagency Fire Center, the top ten costliest wildland fires in the United States have all occurred in California within the last thirty years. More than a dozen fires are currently active in California, collectively dominating approximately 2.5 million acres of landscape.
Throughout the history of recent catastrophic fires in California, there is a clear throughline of human intervention causing undue harm to the state’s ecosystems.
For many residents of the Golden State, wildfire incidents are almost exclusively received as events that put our homes and welfare at risk. This past fire season, in my native Southern California, the Bobcat Fire has threatened 6,000 structures and grown to a size of approximately 115,000 acres. After more than a month, it is still burning, but currently 92 percent contained.
However, not all fires are inherently bad. Whether naturally occurring or human-made, fire is necessary in order to “create the conditions for biodiversity to exist and ecosystems to function,” says Matthew Hurteau, an associate professor in the department of biology at the University of New Mexico. Part of the process of creating those conditions includes burning dead vegetation, cycling nutrients, and exposing bare mineral soil for plant growth, Hurteau says.
From the perspective of ecosystem function, fire becomes catastrophic when it threatens species in the area and creates homogeneous conditions, i.e. conditions that foster the expansion of only a limited set of plant and animal species rather than a diverse set. For example, in forests, fuel accumulation is largely a byproduct of large patches of tree mortality, resulting from previous wildfires.
“Fairly dry things don’t decompose that fast,” Hurteau says. Even after the first ignition event, dead vegetation will continue to interact with future wildfires, causing them to burn more intensely and for longer periods of time. The result would be the forest’s eventual transition to a shrubland, which is inherently a homogeneous ecosystem.
But even the absence of regular fires can cause homogeneity to proliferate. Drawing back on the forest example, trees will begin to grow in between the gaps normally created by habitual wildfires, ensuring ecosystem biodiversity. In this instance, fuel accumulation still occurs, making this area more vulnerable to future fire events.
In California, fire suppression systems have been aggressively utilized over the past 100 years to control ignitions. These systems were specifically designed to put out ignitions when they occur in hopes of suppressing and preventing wildfires. But in fact, fire suppression causes more fuel, such as branches, leaves, and other woodland materials, to accumulate, making future wildfires potentially more disastrous in nature.
Changing climate makes fire suppression systems even less effective, holds Hurteau. Climbing temperatures inevitably decrease fuel moisture in both living and dead vegetation, causing it to become flammable. Moreover, a rise in temperature also increases the number of days per year that dead vegetation is available to burn. Under these circumstances, a large fire will yield even more uniform homogeneity.
These systems have never been effective in Southern California.
Jon E. Keeley, a research scientist in the U.S. Geological Survey’s Western Ecological Research Center and Adjunct Professor at UCLA’s Department of Ecology and Evolutionary Biology, holds that in this region, population expansion and human development are also contributing to increases in fire activity.
In the latter half of the twentieth century, California’s population has nearly tripled in size. To account for this growth, more people have been forced to move into more flammable areas of the landscape. According to the Verisk Wildfire Risk Analysis, over two million properties in California are at high to extreme risk of being affected by wildfires. Therefore, when an ignition event occurs, it is more likely to cause damage than if it had occurred in an area where there was no development.
Furthermore, based on a nineteen-year average of fires and acres reported to the National Interagency Coordination Center at NIFC, humans have caused an average of 4,181 fires per year in Southern California. For Keeley, findings such as these present strong inferential evidence to support the overall hypothesis related to population expansion and human development.
Throughout the history of recent catastrophic fires in California, there is a clear throughline of human intervention causing undue harm to the state’s ecosystems. In large part, this doesn’t come as a surprise. Neither the fire suppression systems nor the path of population expansion was designed in congruence with the state’s ecosystems and fire seasons.
Don Hankins, a professor of geography and planning at California State University, Chico, has devoted a portion of his academic research to Indigenous traditional knowledge and policy, as well as its application in conservation.
When thinking about Indigenous fire burning practices in Southern California, it’s important to understand the historical context, notes Hankins.
According to M. Kat Anderson and Keeley’s “Native Peoples’ Relationship to the California Chaparral,” paleontological, fire scare, and archaeological studies suggest that these fire practices were in use thousands of years ago. Tribes burned the shrubland at specific times of the year and at specific frequencies to support habitats for diverse animal and plant populations. These regular burnings enhanced the reproduction of chaparral species most useful to Indigenous tribes, reduced the competition from other plants, and maintained a state of high growth and productivity postfire. Tribes would then use their yieldings for food, medicine, basketry, and more.
These controlled fires were also designed to reduce villages’ vulnerability to these events by eliminating brush that might carry catastrophic fire. The result was “a mosaic of grasslands, shrublands, and woodlands,” Anderson and Keeley wrote.
For example, according to Hankins, Indigenous people used prescribed fires to encourage the production of California’s oak woodlands in order to subsist on its acorns, as well as other cultural resources. These burns were timed with periodic precipitation, providing the moisture to enable this native species to recover. Overall, oak woodlands are extremely important in supporting the diversity of native species, Hankins attests.
In 1793, the Spanish government of California outlawed the Indigenous use of fire, a policy that began in the Mission of Santa Barbara and spread across the region. Once this practice was removed, chaparral began to expand, and the landscape became subjected to Western techniques of fire management.
Despite the centuries of change, Hankins believes that it is possible to restore Southern California through the reintroduction of Indigenous fire stewardship. Right now, the current timing of the fire season is conducive to reinforcing the seedbanks non-native grasses, especially if fire suppression occurred in that area.
Hankins recommends burning these grasses in the spring when the fuel moisture, i.e. “the amount of water in a [vegetation] available to a fire,” is higher to slow their rate of spread. Then, when the fuel moisture drops, he recommends planting native plant species, such as perennials, to give them a competitive advantage in germinating since they have a better response to fires.
In fact, there are a number of different plant species, such as purple needle grass and blue wildrye, that would increase production from timed burnings.
Overall, Hankins believes that prolonged drought and the absence of these burning practices only increase the area’s susceptibility to wildfires during dry seasons. Today, there is skepticism that these fire management practices can be used in a variety of places across California, which does hinder their future widespread implementation.
Though the topic of restoring Indigenous burning to chaparral is still contested, it’s an option that’s important to explore, perhaps now more than ever.