By Naomi Pitcairn
Special to the Santa Paula Times
A diverse crowd gathered at the Santa Barbara Public Library on the evening of April 26 to hear Fire Ecologist Dr. Jon Keeley speak about chaparral wildfire preparedness.
The invitation for the Los Padres Forest Watch-sponsored event promised topics such as:
— “How our chaparral-covered hills and mountains differ from other fire-prone landscapes.”
— “How humans have changed fire frequency in our region.”
— “How we can best protect our communities from the inevitable.”
Keeley works for the U.S. Geological Survey and is also an adjunct professor at the University of California at Los Angeles and an author of numerous publications. His research has focused on chaparral ecosystems and historical fire patterns in California and their relationship to climate, urban development and invasive plants.
How do chaparral-covered hills differ from other fire-prone landscapes?
Over the last century, forest fire management has drastically reduced fires in the Sierras, but our coastal chaparral environment is significantly different from the forests of the Sierras. Climate and weather are different. The plants are different. There are chaparral plants that cannot exist without fire, indicating that chaparral burns naturally, although today it is burning much more frequently than it used to.
Lightning-ignited fires probably burned in coastal California once or twice a century prior to the arrival of Native Americans. Today, because of human activity, lands are burning often enough
that we are at risk of losing some of those fire-resilient plants. That is because the increased frequency of fires does not allow these plants enough time to accumulate seeds sufficient for
regeneration after fire. Global warming may be also a factor, as it favors fast growing, non-native invasive grasses over the native-shrub regeneration.
Humans have changed fire frequency in our region
Keeley began his talk by discussing the October fires in the North Bay. He put up a graphic that superimposed the fire boundaries of the 2017 Tubbs Fire with the 1964 Hanley Fire. The graphic made it immediately clear that the Tubbs fire was almost a mirror image of the Hanley fire half a century ago. We’ve had increasing fires in past 50 years, yes, but we’ve also had big fires
in the past. The significant difference is that in the 2017 Tubbs Fire, 43 lives and 5,643 structures were lost, whereas, in the 1964 fire, no lives and relatively few structures were lost. There are two reasons for the difference, according to Keeley: Population growth (more people are living in fire-prone areas today) and freak weather events (in this case a high-pressure cell in 2017, generating extreme winds).
The local Thomas Fire also had atypical winds created by a high-pressure cell in the interior with low pressure off the coast. This was a weather event and Keeley made the point that climate
does not tell us about events such as:
1. Heat waves and extreme wind events.
2. Long-term droughts.
3. Patterns of ignition.
4. Land management and use (pre- and post-fire).
All of these things affect fires, along with climate change. Research suggests that in coastal California, global warming probably won’t have a large impact on the number of fires or area burned, but may favor annual exotic species that come with their own set of problems.
What about temperature, precipitation and fire?
Studies show that in the Sierras, spring and summer temperatures can dictate how much burns, but spring and summer temperatures do not affect our chaparral-covered South and Central Coast. The same thing goes for annual variations in precipitation: It is significant in the Sierras, but not so much on the coasts. The Sierras don’t burn every year because they don’t dry up enough every year for that to happen. Here in Southern California, it is hot and dry enough to burn every year, so there are other things that determine our fire situation. We can explain the variation of fires in the Sierras better than we can here and all of the Sierra forest research is not applicable to our area.
What do we know?
According to an infographic of seasonal temperatures taken at the Cheseboro Weather Station in the Santa Monica Mountains, this past year’s winter temperatures were not abnormally high, although summer and autumn temperatures were higher than average. Data from this same site, however, has shown that most of the last six years have been abnormally dry. Although this past winter there was higher-than-normal rainfall, the long-term drought has resulted in mortality of many shrubs in the chaparral and this is thought to have contributed to the size of the Thomas Fire.
Freak wind events
Many climatologists are weighing in “new normal,” said Keeley, and a lot depends on the period of time one is looking at. Santa Ana winds are typically associated with autumn. November is the peak. Significant fire in December here is not typical, but is not an anomaly, either. Keeley brought up charts that showed several significant December fires in California history that were blown up by hot winds. Due to the unusually stable high/low pressure event of this past December, however, a remarkably persistent weather pattern developed over North America and the Pacific. This weather pattern caused the Santa Ana winds to blow far longer than any previous wind event, about 10 days. The Matilija fire wind event, in comparison, lasted five days. Is that to be the new normal?
Ignitions
Ignitions have been declining since 1980, although not necessarily burn acreage. Fire-prevention programs in the last 40 years appear to have had an impact. This decline has not happened with
all sources of ignition, however. Arson is down, but power-line-ignited fires have not declined. Power-line fires generally don’t start, except in high-wind events that that either blow down lines or cause them to arc. An audience member mentioned that our power line poles are only rated at 55 mph. Although Keeley suggested that one viable solution would be underground power lines
in Santa Ana wind corridors, San Diego Gas & Electric Co, which was heavily sued after the 2007 fires, claims underground lines are too expensive. Instead, they are monitoring wind speeds and
plan to shut off the power grid when winds exceed 80 mph.
Of course, people will complain and maybe go buy generators, which can start fires as well, so the situation is not ideal. Other solutions that have been brought up include stronger power poles and solar. It is the opinion of some that the courts are probably going to force the power-line companies to rethink things in some way or other.
Pre- and post-fire management
Prescription burns seem to have had no impact on the spread of the Thomas Fire and no real impact on stopping wind-driven fire events. In Montecito, Keeley said, maybe pre-fire management could have had an impact in some areas where vegetation was substantially older than other areas within the Thomas Fire because older chaparral accumulates more sediment, but it’s not entirely clear because the extremely steep landscape was a big factor.
The majority of Southern California fires burn in August and September during Santa Ana winds. Fires in July and August, however, indicate that big fires can occur without these extreme winds. Big fire events seem always to be preceded by extreme drought, meaning droughts that last several years. The huge Cedar fire followed 54 months of extended drought. Extended drought creates a dieback of foliage, which increases the fuel load. Records from the Cheseboro Weather Station near the Thomas fire area indicate that the drought didn’t end after 2014 as it did in the rest of California.
There was extensive dieback in local chaparral, likely the legacy of the four-year extended drought. Extended drought likely plays a role by producing dieback that creates lots of fine fuels that help spot fires start. If embers land on live shrubs, they probably will not ignite, but dieback could increase spotting behavior. Dieback is one thing that makes Keeley sometimes rethink prescribed burn.
Seeding vs. physical barriers
Seeding works in other places, but physical barriers are more effective in California where rains come all of a sudden in winter, washing everything off of the slopes, including the seeds. Non-native rye grass has been used for seeding, but doesn’t seem to reduce post-fire erosion. Native flora comes back better than seeded species. New problems also can arise from new solutions. When mustard was used for seeding, it washed down into orchards and farmers complained. Diverting sediment that runs off with sandbags and hay bales and other physical barriers is the most effective post fire management, according to Keeley.
Home preservation, defensible space
Brush clearance is mandatory 10 feet from roads and 100 feet from dwellings in our local counties. Clearing around houses is important for providing defensible space for firefighters. Most houses however, studies show, burn from embers. There are two main ways homes in our area burn:
1. The correct protective vents were not installed and embers were sucked into the buildings because of temperature potential (difference).
2. Trees hanging over roofs. The issue being that the dead leaves that accumulate on the roof and in the gutters ignite when embers land in them. It would appear that these affordable
improvements could make the crucial difference in preserving a structure.
Methods and priorities
Fact: Firefighters don’t put out fires in extreme wind events. They evacuate people in front of the fire and try to contain the edges of the fire and wait for wind to calm. Agencies are primarily concerned with keeping people alive. Keeley stressed the importance of having one person in charge during a fire event. You have to have one person in charge and it has to be decided ahead of time. It is too hectic during a fire to change strategies easily. Different agencies can have a difficult time working together. An audience member asked about why military help was not used during the Thomas Fire and we learned that the military is not even on same frequencies as our CalFire and Forest Service. It can be dangerous to try to coordinate different groups with different leaders in an event like this. One leader. Really important — a fire event is extremely chaotic.
Fuel breaks
Several studies have found that vast fires never affect the majority of breaks because fires didn’t happen to occur where they were created. Fuel breaks are effective when they provide access
to firefighters to start backfires, but not effective on their own.
Fuel breaks need to be installed strategically to provide access to firefighters where there is something specific to protect. Fuel breaks are not firebreaks. The difference is that fuel breaks are constructed prior to fire events where firebreaks are constructed during a fire event.
There was some discussion on shaded fuel breaks as well. Shaded fuel breaks have a reputation for being effective in forested systems where fires burn in understory. But this is another example of how forest fires are different from chaparral fires. In forests, winds are more suppressed, which creates a different kind of fire system and makes it hard to apply what works in the forest to chaparral.
Repeat fires
Fires are on the increase partly because humans have been replacing perennial vegetation with annual vegetation that produces more food crops. Our native Ceanothus would not survive without fire, but repeat fires replace native with exotics. Repeat fires can happen within several years now. Some species like Ceanothus need about 20 years to recover, so frequent fires will eliminate certain species. Invasive annuals move in with repeat fires, which creates a trend.
More reading on this topic is available in the Los Padres Forest Watch’s Spring 2018 issue: https://lpfw.org/wp-content/uploads/2018/05/LPFW-Spring-2018-Newsletter_web.pdf
— Naomi Pitcairn watched the Thomas Fire from her South Mountain Road home for 11 straight days in December.
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