In a year that is already being called one of the worst ever for wildfires in the western United States , there is another fact that some may find remarkable: For nearly 40 years, the number of wildfires in California has been declining.
California wildfire data reviewed by a USGS research ecologist shows a trend that many may find hard to believe: Since a peak in 1980, there have been fewer and fewer wildfires in California. This is true across the entire state, according to researcher Jon Keeley, who is also a professor at UCLA.
According to his paper, co-authored with Alexandra D. Syphard, we need to rethink our ideas about the frequency of wildfires.
“The claim commonly made in research papers and the media that fire activity is increasing throughout the western USA is certainly an over-statement,” wrote the authors.
The trend of fewer, but not smaller fires is apparent in recent years. State data regarding large wildfires (300 acres or more) from 2000 to 2015 show total numbers – not fire size – has been in decline, despite a sharp spike in 2008.
So, what’s the reason for this decline? Well, they don’t know… yet.
“Can’t say at this point what has changed in the last 100 years that has caused this decline… but I am hoping we might find out,” Keeley said.
What might be behind a decline in wildfires?
Keeley has just begun to analyze the data and look for a reason, but he expects to finish that analysis by the end of September. He is also sending his research to Calfire for review.
Keeley is confident the culprits behind the decline can be narrowed down to two options – prevention or climate – but he is reserving his judgment for now.
“Maybe fire prevention strategies or could be related to climate,” Keeley said. “My guess is they would probably like to think it is increasing efficiency in fire prevention but remains to be seen if that is the answer at this point.”
Keeley is hoping Calfire might be able to point to some specific prevention strategies and dates they were implemented to help him suss out if they had a major impact in wildfire declines.
“We definitely have the education side,” Calfire spokesman Scott McLean said. “We spend a lot of money being proactive in trying to educate the public.”
While McLean said the organization has adopted social media and other modern tactics in recent years to better reach the public about fire prevention, Calfire’s educations efforts have been happening for decades.
“There are some embarrassing programs out there with blue leisure suits and mullets,” he said.
McLean said a decline in the amount of wildfires was a win for the agency’s outreach programs since the majority of wildfires are the result of human causes.
“I love to see the trend of wildfires going down,” McLean said. “That means we are getting the message out.”
While the amount of wildfires has gone down, something else has been happening
Despite the decline in overall fires, the amount of acres burned by wildfires isn’t following the same trend. In fact, acreage burned by wildfires is doing just the opposite.
“For most ignition sources we have found a decline in the numbers since the 1980s, but not a decline in the area burned,” Keeley said.
Large wildfire numbers from 2000 to 2015 illustrate the growth in burned acreage. While the numbers are volatile year to year, the overall trend shows growth in fire sizes.
McLean attributes the growth in acres burned to environmental factors that have made fires burn hotter and faster than in the past. Despite that, he credited Calfire for its work in keeping the majority of fires from spreading. According to Calfire data, 95 percent of fires are kept under 10 acres.
“We are constantly training. We always pay attention to what is going on, we always investigate,” he said. “We investigate what took place and we learn from it and we make sure our firefighters learn from it.”
One reason acreage may be up is from the record winter rains that replenished fuel for fires by spawning plant growth, including the return of grass that had disappeared from wildland areas throughout Southern California during the drought.
Grass fires tend to burn faster and increase the amount of acres burned, according to a 2008 paper published by UC Merced Sierra Nevada Research Institute’s Anthony Westerling.
“Moreover, the presence of fine fuels within a region may also give rise to higher monthly mean acres burned, because fine fuels—grasses especially—regenerate faster than heavy fuels, shortening the interval between burns. Finally, the tendency for area burned to be greater in areas characterized by fine fuel types is strongest early in the fire season (June), and may simply reflect the earlier arrival of warm, dry summer conditions at lower elevations.”
Other researchers point to climate change, but Keeley says he thinks there may be other variables at-play.
“People who have written on it tend to ascribe it to climate change, but I think we are a long way from knowing if that is what is going on,” he said.
2017 trending in the wrong direction
During the last 40 years, there have been a number of years that have bucked the trend of dwindling wildfire numbers and 2017 is already well on its way to being one of those outliers.
As of Sept. 11, Calfire has reported 5,102 wildland fires in their jurisdiction with nearly 230,000 acres burned. During the same time period in 2016, there were 3,803 wildfires and 204,000 acres burned. The five-year average has been 3,872 wildland fires and 155,807 acres burned, according to Calfire.
2017 is also the most expensive year for wildfires as Montana, Washington and Oregon, among others, have all been hit by devastating blazes. As a result, U.S. Secretary of Agriculture Sonny Purdue announced Thursday the cost of fighting fires has exceeded $2 billion. It has also been a record-setting year for heat in California and other western states, according to the National Climate Report produced by the National Oceanic and Atmospheric Administration (NOAA).
While 2017 has been worse than predicted across western states after there were hopes a wet winter would diminish the fire season, McLean wasn’t surprised by the numbers considering the years of drought and the fuel created by the rain that preceded fire season.
“As a firefighter, you wake up in the morning ‘what’s the weather doing’ because that tells you what your day is going to be like,” he said.
