Wildfires
Wildfires are a natural process in many ecosystems in Arizona. Records from the 19th century indicate frequent low intensity fires occurred every 5-25 years. Frequent burn patterns eliminate buildup of excessive woody fuels such as branches, pine cones and grasses. Fires also keep tree density low as young trees are more vulnerable and encourage biodiversity by allowing more light to reach the forest floor. Northern Arizona is home to the largest contiguous ponderosa pine forest in the world, covering 2.6 million acres. Mature ponderosa pines are adapted to fire with thick inflammable bark and natural shedding of lower branches. These low intensity fires stay at ground level, rarely burning to the top of a mature tree.
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Why are there more wildfires?
Unfortunately wildfires are increasing in frequency and severity. Many factors contribute to this change. Settlement of the West in the late 19th century introduced intense livestock grazing. Many native grasses could not survive and invasive species were introduced and spread disrupting the natural fire cycle. Fire suppression policies reduced healthy low intensity burns leading to buildup of woody ground fuels and crowded weak spindly trees. A mature ponderosa forest contains 20-60 trees per acre. Today 300-1,500 trees per acre is common. These trees are more susceptible to diseases such as bark beetle and dwarf mistletoe infestation.
Human induced climate change are contributing to drought and record heat. Our already susceptible forests now burn with such high intensity that mature trees no longer survive. Post-wildfire forests are transformed into shrubland and grassland.
How do wildfires harm humans?
Wildfires harm humans in many ways. Wildfires can move quickly, on average 14 miles per hour. The immediate risk for those living in fire prone areas is becoming caught in a wildfire and unable to escape as recently seen in California and Hawaii. Furthermore, smoke contains many harmful pollutants, including particulate matter, carbon monoxide, nitrogen oxides and ozone precursors. These pollutants can travel thousands of miles, affecting large populations. Exposure to smoke contributes to coughing, eye irritation, asthma, bronchitis and COPD exacerbations. In 2023, 100 million Americans were exposed to wildfire smoke. Smoke is also associated with increased heart attacks and strokes and is responsible for hundreds of thousands of deaths annually. In the aftermath of a fire, the ground is more susceptible to erosion. This contributes to flooding, contamination of drinking water, loss of pollination and farming land. Mental health also suffers in communities affected by wildfires.
How can we protect ourselves?
Fortunately there are steps that we can take to protect ourselves.
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Forest health and resilience can be achieved through national policies such as prescribed wildfires and thinning of tree density. Educate yourself and support local and national policies that address forest health. https://www.doi.gov/wildlandfire/policy
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Monitor air quality and avoid outdoor activities when air quality is poor. https://www.airnow.gov/
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If you live in a fire prone area, become a Firewise certified neighborhood. https://www.nfpa.org/education-and-research/wildfire/firewise-usa
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Human caused climate change is contributing to megafires. Local and national policies are essential to addressing greenhouse gas emissions. Vote for climate conscious leaders. https://voteclimatepac.org/