Chaparral Vs. Fire (manuscript)

Chaparral is a rare biome found in few places throughout the world, one of them being southern California. Chaparral is recognized by its woody drought-hardy shrubs, Mediterranean-like climate, and wildfires. Now, the wildfires are where the controversy comes in. Due to the misunderstandings of the Chaparral, it is being managed poorly and thus having greater problems. Chaparral is extremely beneficial to California due to the essential protection it provides against soil erosion, its moderation of climate, its underground water supplies, and its habitat for flora and fauna. While urban sprawl is quickly dominating the region, fire management is taking many different extremes. Some believe that frequent fires are necessary to maintain biomass build up, while others counter that the region should not be managed with fires at all. A burning system in between the spectrum is the best answer. Due to the growing urbanization, fires can no longer be completely wild and must be managed to ensure the chaparral can maintain its sustainability. Today I will describe the California mosaic hypothesis and another contrasting view, a brief history of the land, and provide a quick overview of the naturally occurring flora.

The Department of Sustainability and Environment describe the California mosaic hypothesis as, “Applying planned fire at varying intensities, scales, and times within a broader landscape to create patches of burnt and unburnt areas that change over time” So, the idea is that biomass will accumulate, and, if not managed, create a larger, hotter, and less controllable fire. However, when chaparral is burned too often, certain plants that aren’t as tolerant to the flame can be lost and invasive weeds can take over. It takes Chaparral about two years before it truly flourishes with density and diversity after a fire, and it cannot reach that potential if everything is consistently being burned away. Poor burnings can also lead to soil erosion. On the other hand, The California Chaparral Institute believes that fire is not necessary at all to maintain a healthy ecosystem… but doing nothing can encourage larger out of control fires. Allowing fires to occur naturally, or preventing them completely, can be unsafe due to the volatile oils in the plants that allow flames to spread to different flora easily. One of the largest factors of uncontrolled wildfires, besides the easy combustion of the oils, is wind, especially the Santa Ana winds which can spread fires quickly and in many directions. The four contributors to out of control fires, and thus the at risk concern of people and property, is heat, oxygen, fuel, and weather. Another concern of a zero fire regime is the important flora, such as mariposa lilies and fire poppies, that need the extreme heat or char in order to germinate as well as fire being a key source in helping nitrogen bound in organic material to transform into ammonium which is directly usable for flora to prosper.

And now a brief history: Ethnographic studies support that the land was once maintained by aboriginals who would manipulate the land with fire as a means for better hunting opportunities, protection, and warfare strategy. Despite the fires being more frequent than the average fire induced lightning storm, two recorded in the past twenty-five years, they still allowed the area to thrive. Once settlers began to migrate to southern California, though, the land was left vulnerable to invasive European grasses. The invasive grasses can take over if the native plants aren’t cared for properly. Frequent fires were still practiced in the 1800’s which is when the first massive wildfire took place. The Tujunga wildfire occurred in 1878 and became unmanageable due to the Santa Ana winds. The second wildfire didn’t occur for another 20 years providing evidence that wind is a larger factor than biomass buildup.

Next I will discuss the chaparral flora. The flora in chaparral has developed modifications to help survive during and after fires. There are three main types of fire modifications that the chaparral flora has developed. There are the obligate resprouters, obligate seeders, and facultative seeders. Obligate resprouters are plants, such as the toyon, that depend on resprouting under the earth after a fire for survival. Obligate seeders can be perennial shrubs, such as the ceanothus species, and are terminated in the fire and rely on the fire affected seeds to restart the next population. Faculative seeders, such as manzanita, resprout and germinate after a fire passes through. Making things more complicated, when fires are too hot, they can destroy the buried root crowns of vegetation, making it more difficult for plants to regenerate which can allow coastal scrub plants to take over, altering the ecosystem.

According to California Fire, “From 1997-2001, an average of 392 wildland fires were caused by arson, burning 21,072 acres and causing over $3.2 billion in damage annually”

To sum up: The urbanization and conflicting views create a strain on fire management in the chaparral region of southern California. The chaparral has adapted a resiliency to flames and even requires them in order for flora to be at their peak. Mosaic burning and suppression can be more harmful to the flora than helpful and cause insufficiencies in diversity and density. By having a system of fire management, planned at the right season and maintained to where is can cleanse the biomass, the houses will be safe and the ecosystem can thrive. 

Amanda Cully, Communication 490, Humboldt State University, Fall Semester 2013

Recorded  September 25, 2013 - Episode D