This project in California supports the restauration of forests lost through wildfires and improves resilience to future wildfires and bark beetle infestation.
California Fire Season?
In Northern California, peak fire season begins in the early Summer (June-July) and runs until late October, varying year to year. In Southern California, the peak fire season begins in late spring (May-June) and runs until end of Fall. The precise timing varies according to annual and seasonal precipitation, as well as the occurrence of offshore wind events, such as the Santa Ana winds, Diablo winds, or Sundowner winds. With climate change as a contributing factor, however, the season is beginning earlier and ending later each year. Some experts suggest that the fire season in California is now year-round, and wildfires are possible at any time of year in the state, particularly in drier Southern California.
What Causes Wildfires in California?
California’s dry climate, abundant winds, and dried vegetation provide prime conditions for a wildfire.
Nevertheless, due to several factors the number and the severity of wildfires keeps increasing, and during the recent years many more acres are burning compared to previous decades of the state's recorded history:
1) Climate Change:
The long-term trend shows that wildfires in California are constantly increasing mostly due to anthropogenic climate change, with long-term droughts, extreme heat, earlier start to the growing season, and a reduced snowpack (Sierra Nevada) contributing to the severity of the fires. Global warming has led to weather and vegetation conditions more favourable for wildfire activity.
The state of California is experiencing drought conditions on a number of timescales. During the last years the state sees very little precipitation with much of the state experiencing its driest such period. This dry period is part of an ongoing 22-year spell of drought in the North American West that marks the driest such period in at least 1,200 years, according to scientific research based on analysis of soil moisture deficits and tree rings.
The drought has impacted wildfire risk and severity in a number of ways. Increased dryness of fuels, driven by increased vapor pressure deficit (VPD), a measure of the aridity of the atmosphere, is behind an eightfold increase in the area burned by wildfires in the Summer in California since 1972, according to scientific research.
Drought and overcrowding have also made forests more vulnerable not just to wildfires but bark beetle infestation, which has further weakened and killed forests. Total tree mortality since 2010 exceeds 172 million, providing plentiful fuel for wildfires.
2) Forest Management and Fire Suppression
Another reason for severe wildfires is the increase of biomass, due to insufficient controlled burning, resulting in a build-up of fuel, increasing the risk of large uncontrollable fires. There is broad scientific consensus that there should be more controlled burning of forests in California in order to reduce wildfires.
And beginning with the advent of the U.S. Forest Service's '10 AM policy', in which it sought to extinguish all fires by 10 AM the morning after their report, the primary method of wildfire management in California has been suppression. The success of this approach has led to a further surfeit of fuel, resulting in even larger and more extreme fires ("megafires").
3) Wildland-urban interface development
California, as with other areas of the United States and the world, has experienced a growing amount of human development into the wildland-urban interface, or WUI. This area consists of developed areas either adjacent to, or intermingled with, wildland vegetation and fuels. Such areas are more prone to wildfire ignitions and structure losses, increasing the risk and severity of fire seasons in California.
And it only takes a single ember to ignite and destroy hundreds of thousands of acres. While wildfires can occur due to natural causes, 85-90% of wildfires are caused by human activity.
Some of the most common causes of fires in California include:
- Burning Debris: Escaped embers from burning debris is one of the most common causes of wildfires. On a windy day, escaped embers can carry for miles without extinguishing.
- Unattended Campfires: The Ham Lake Fire, which destroyed 75,000 acres and hundreds of properties, is just one example of the devastation that a single campfire can cause.
- Downed Powerlines: Over the past six years, over 1,500 Californian wildfires were caused by fallen power lines, including the deadliest fire in history, the Camp Fire.
- Discarded cigarettes, lightning strikes, engines sparks and other events can alos start wildfires.
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