January 20, 2012
Fire in the South Coast Bioregion
Although wildfires are normally associated with the immediate destruction they also have necessary function and a place in many ecosystems. Some benefits from periodic wildfires include the removal of accumulated dead wood, which may have been building; this then gives plants requiring higher levels of sunlight the opportunity to flourish. This excess of land also gives animals a chance to forage or nest. In addition to its land clearing capabilities, fires can be the stimulant enabling some plants to distribute their seeds and provide conditions allowing seeds to germinate. For these reasons it is clear the misconception that fires are bad is false. When viewed on a larger scale of multiple years or decades it is obvious that fires are a natural component of an effectively functioning bioregion.
Wildfire occurrence in the south coast bioregion is endemic. The dry climate of the natural desert of Southern California is a perfect catalyst for naturally induced fires. The boundaries to this area are the Transverse mountain ranges, the US border with Mexico, the peninsular mountain ranges, and the Pacific Ocean (this area does include the channel islands) – North, south, east and west respectively.
Lightning is often a frequent source of ignition for wild fires. This is not, however, the case in the winter and early spring, when ocean winds delay the onset of fire season in the coastal regions. Additionally the colder and wetter climate of the region at this time of year moistens the organic life making it harder to ignite.
An important contributory factor affecting fire occurrence in the south coast bioregion is the Santa Ana winds. These winds force hot dry air toward the coast. Firstly, they are preferred conditions for a fire to start and secondly, they occur at a time in early autumn when the plant life is at its driest and most susceptible to fire. Fire will also spread more rapidly due to the dry climate and the dry Santa Ana winds if a fire outbreak should occur.
Both lightning storms and foehn winds such as the Santa Anas overlap briefly, accounting for naturally occurring fires. However, in modern times, wildfire ignition is predominantly associated with human activity, and as such the surrounding bioregion has been exposed to a disproportionate number of fires what is deemed natural.
Although fires can serve a biological function, excessive fire to the organics of southern California is damaging to the previously mentioned organics and thus puts unnecessary strain on the local bioregion. This raises a moral question as to how human involvement is putting a strain on the south coast bioregion due to accidental fire ignition.
In the Sidebar 15.1 section, Keeley compares the fire regimes of Southern California to Northern Baja California. In 1975 United States’ scientist Dodge believed the burning patters would be different between the chaparral and coniferous forests depending on the side US/Mexico border. They believed Mexico did not practice fire suppression outside of towns and that fires were actually encouraged. Dodge found the “lack of fire suppression, frequent burning of the shrublands, and over-gazing Baja California” (Keeley 361) suggested land use patterns were the same above and below the border (361).
In 1983, Minnich compared burning on both sides of the border between 1972 and 1980 and found that fires were larger on the US side of the border (361). Critics, however, dispel these findings because they are based on two reports of large fires north of the border, but written records of fires south of the border were not available. The historical aerial photographs Minnich used in their place did not suffice, according to Keeley (361). The conclusion is the smaller fires south of the border represent the natural fire regime, and that the larger fires in southern California are a result of human induced fire avoidance. The fuel for the fire thus accumulates immensely for years, and the resulting fires are huge (361). This conclusion too is criticized because with fire suppression, large fires in southern California have not increased. In terms of comparing conifer forests, scientists attribute differences in forest structure as the reason for the differences in fire frequency.
Fulé et. al, studied fire occurrences in Chihuahua, Mexico. They found the prevalence of fire control regimes led to more severe wildfires, thus surface fire should be used as a management too, thus contradicting Keeley’s argument against Minnich’s conclusion that fires increase in strength with the accumulation of fuel with human-induced fire prevention.
Keeley also asserts some scientists believe climate could play a more prominent role than fire management policies. However, Keeley demonstrates the three-degree difference in latitude shows only few differences in forest structure and species.
Forrest and Harding state:
“People and their activities are as much a part of the post-fire environment as are native plants and animals, and any approach that does not incorporate human resources and values as part of a mitigation strategy fails to appreciate the practical interface between humans and their environment.”
While Forrest and Harding’s statement may be anthropogenic and optimistic, there is an important point to apply to Keeley’s study. Forrest and Harding affirm Keeley’s statement that humans drastically affect their environment. Human stewardship of land will determine its ability to function in its natural state.
This post was written by Elise Fabbro, a double major in Political Science (BA) and Environmental Studies (BA) who is currently pursuing her MA in Environmental studies, and by Richard Charlesworth a senior in Environmental Studies (BA) with a minor in Architecture.
Works Cited
Forrest, Carol L, and Harding, Michael V. ”Erosion an sediment control: Preventing additional disasters after the Southern California fires. ” Journal of Soil and Water Conservation 49.6 (1994): 535.
Keeley, Jon E. “South Coast Bioregion.” Fire In California’s Bioregions. 350-91. Print. Peter Z Fulé, José Villanueva-Díaz, and Mauro Ramos-Gómez. ”Fire regime in a conservation reserve in Chihuahua, Mexico. ” Canadian Journal of Forest Research 35.2 (2005): 320-330.
I’d be interested in further studying fire in conifer forests, as briefly reference in the posting and article. As the focus of the articles is Southern California, most of the information regards the dry chaparral ecosystem and a Mediterranean climate. Perhaps it is because I am from Southern California, but I mainly feel that large fires that are huge threats are in the Southern California region along with other southern areas and dry Midwest regions. While the climate that supports a conifer forest is wetter and therefore less prone to fires in this way, I would think that a large accumulation of conifer needles and pine cones, for example, would be strongly fuel wildfires. Dead needles, which are dry, small, and cover the floor, would seem especially adept at spreading fires over long distances. It would be very interesting to look into some data about the fire window and strength of fires in this different biome.
I found is post very interesting because I am a native of Southern California and the subject of wildfires in the coastal bioregion. I noticed that most of the wildfires occur in the chaparrals, in which the climates are very dry, which makes fuel for wildfires to occur. Also I noticed that you made a point regarding the human involvement in the creation and prevention of wildfires. This is interesting because it brings up the question of whether how far we as humans should get involved in preventing fires in Southern California? This is especially important because as much as we wish to protect the chaparral ecosystem we also need to take into account that organisms need the temperature of the fire in order to develop.