The Dangers of Wildfires

| April 2, 2018 | 0 Comments

The residual effect of fire fills the skyline.

In January, Gary Ferguson, author of “Land on Fire,” pointed out some of the benefits of fire. However, wildfires have changed. They are more frequent, burn hotter, and burn more acreage, cause more damage, and kill more people. Why?

Combustion cannot occur unless there is fuel, oxygen, and heat. Since July there have been about 9000 fires costing over $500,000,000. In Ferguson’s book he says that in the early years of the 21st century there were more than 12 “megafires,” fires, which burned more than 100,000 acres. In the United States, firefighting often costs more than two billion dollars per year. In the past half-century there were four years during which more than nine million acres burned. Ferguson says according to firefighters, “99 per cent of the burned land comes from 1 percent of the fires. In North America, megafires actually constitute fewer than three percent of the fires but currently account for more than 90 percent of land burned.” He continues, “Big fires are becoming common fare.”

Higher temperatures and lower humidity are products of climate change. Fire seasons are longer than those in the past. Warmer days and more rain-free days have caused the season to become 18.7 percent longer according to South Dakota State University in 2015. Ferguson clarifies this: the amount of rainfall is about the same, but more rain falls on fewer days meaning “more dry days when conditions are right for wildfire to occur.” Forest Service records show that since 1972 the fire season has increased by about ten weeks. In the West, about a month after the snowpack melts, fire season begins. Our snowpack has been melting several weeks sooner than it did in the 19970’s. The hot, dry weather continues further into the fall, which lengthens the fire season.

Many factors add to the heat of today’s wild fires. Thanks to the pine bark beetle infestation, thousands of acres of forest have died or are sick, leaving pitch on their trunks as they try to expel the beetles inside. Since our climate is warming and drying, insects are thriving and multiplying in the West. Those that dine on trees are creating kindling of the trees. This is fuel.

Humans’ habitat is also responsible for increasing wildfires. Communities built along “open space,” national parks, conservation preserves and other “natural” landscapes allow what Ferguson calls “wild land fuels” to exist with man-made structures. 44 percent of the 2.3 billion acres of the United States are considered wildland-urban interface (WUI). 220 million acres has been designated as high-risk areas for wildfires.      About one third or more of the population of the United States live in wildland-urban-interface; more than 80 percent of these are undeveloped.

Wildfire fighters keep 97 percent of the approximately 100,000 fires to fewer than ten acres in size, but the WUI has seen enormous losses due to fire. Between 2000 and 2017 nearly 40,000 homes and businesses in the WUI have been lost.

Ferguson pointed out that in populated areas of California, lightning caused only 4.2 percent of destructive wildfires. The homes and their inhabitants are no doubt responsible for the rest.

Loss of land and property is not the only negative aspect of these wildfires. Air quality puts many people at risk. Wildfire smoke is made up of particles and gases. These play havoc with the lungs, eyes, noses and throats. Itchy eyes and runny noses are not as serious as the risk of bronchitis or asthma attacks. Unborn babies may have a lower birth weight, especially if their mothers were exposed to the smoke in the second trimester.

Ferguson explained that adjusting to climate change took eons. Today conditions are changing faster than life can adapt. Due to warming conditions at higher elevations which results in changing flora, many species are already disappearing; the pika, the smallest of the rabbit family, one such species. So is the white-tailed ptarmigan, which depends on treeless plains in high altitudes. Drying streambeds prohibit cutthroat trout from spawning. Amphibians are losing the wet places where they have thrived for years.

The drier ground has caused much of our native grasses to disappear leaving the land open to less nutritious invading grass species. This upsets the food chain as less nutritious graze means fewer healthy capybara (hydrochoerus hydrochaeris) or grazing herbivores. This leads to fewer predators and scavengers. More importantly, native grasses evolved with fires; invaders did not and they too may eventually disappear. Burned landscapes can attract invasive species. Cheat grass, which came from Eurasia, flourishes shortly after a fire. Sadly, it also dies by early summer and becomes fuel. It burns hotter than most native species, which often causes the natives to become extinct giving more room for more cheat grass. According to Ferguson in “most of Nevada, half of Utah, and portions of Oregon, California, Idaho and Wyoming, cheat grass is the dominant ground plant across some 25 million acres.”

Medusahead is another invasive plant that thrives after a fire. Not only can it produce 1000 plants per square foot, it is low in nutrition and, being high in silica. It slows decomposition of dead plants, which means instead of feeding the soil, the dead plants become fuel for more fires.

Extremely hot fires can render the soil “hydrophobic.” Fire resistant organic matter often has a wax-like substance to protect it from water loss. If the fire is hot enough to burn the organic matter, the wax vaporizes, cools and coats the soil. Water runs off the soil causing floods and mudslides, contaminating water supplies.

These problems come about due to our hotter and more frequent fires and from the 80 years forests were not allowed to thin naturally with normal wildfires.

Next month we will look at Ferguson’s suggestions for what we can do to protect ourselves.

The garden club will meet from 6 to 8 p.m., Wednesday, May 23 at 1525 Fort Stockton Drive at Mission Hills Nursery.

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About the Author ()

Barbara Strona is a native Californian who grew up in the Mid-West and Los Angeles. She and her architect husband, Carl, came to San Diego in 1968 and have lived in Mission Hills since early 1971. Barbara received a Bachelor of Arts from Scripps College with a major in English, and a minor in Art. She attended UCLA graduate school and received a General Secondary Credential. She taught English in Los Angeles, Pennsylvania, and at Point Loma High School. She has been a Realtor specializing in residential sales since 1984. Her passions include her job, reading, writing, foreign languages and foreign countries, animals (feathered or furry), theatre, and her family: husband, two adult children and two grandsons.