Open Letter: To Decision Makers Concerning Wildfires in the West
Wildfires have shaped the ecology of western ecosystems for millennia, whether lit by lightning or managed by American Indian tribes for cultural benefits. Wildfires vary in intensity and occurrence, across regions and vegetation types, elevation and climatic gradients, so there is no one-size-fits all strategy. The West has always burned and will always burn, and it needs to in order to maintain ecosystems and the myriad services they provide to the public in the form of carbon sequestration, clean water, abundant wildlife, and outdoor amenities. Attempting to suppress fires that are not a risk to communities is impractical, costly, risky to firefighters, and ecologically damaging. Also, forests are not the majority of the area burned annually on average in the United States; grasslands and shrublands are a large component of area burned annually that is unaffected by any forest management.
What is different today about wildfires is they are now burning over larger landscapes (more acres) since the 1980s, although overall fewer acres are burning today compared to that estimated in early decades and historical timelines. Wildfire season in the West recently has lengthened from an average of five to seven months, and the number of large wildfires (>1,000 acres) has increased from 140 to 250 per year. This is occurring as average annual temperature in the West has risen by nearly 2 degrees Fahrenheit since 1970s and winter snow pack has declined. Increases in acres burning can now be attributed, in part, to climate change and the increase is expected to continue in many areas with additional warming, leading to even greater suppression costs and loss of life.
In addition to climate change, more than 80 percent of fires nationwide have been caused by people, and millions of homes are now in harm’s way, resulting in skyrocketing costs. Putting more money into fire suppression will not reduce homeowner losses as long as homes continue to be built next to fire-adapted ecosystems, lack defensible space and/or fire-proofing, and measures are not taken to reduce human-caused wildfire ignitions.
When fire weather is not extreme, thinning-from-below of small diameter trees followed by prescribed fire, and in some cases prescribed fire alone, can reduce fire severity in certain forest types for a limited period of time. However, as the climate changes, most of our fires will occur during extreme fire-weather (high winds and temperatures, low humidity, low vegetation moisture). These fires, like the ones burning in the West this summer, will affect large landscapes, regardless of thinning, and, in some cases, burn hundreds or thousands of acres in just a few days. Thinning large trees, including overstory trees in a stand, can increase the rate of fire spread by opening up the forest to increased wind velocity, damage soils, introduce invasive species that increase flammable understory vegetation, and impact wildlife habitat.9 Thinning also requires an extensive and expensive roads network that degrades water quality by altering hydrological functions, including chronic sediment loads.
The recent increase in wildfire acres burning is due to a complex interplay involving humancaused climate change coupled with expansion of homes and roads into fire-adapted ecosystems and decades of industrial-scale logging practices. Policies should be examined that discourage continued residential growth in ecosystems that evolved with fire. The most effective way to protect existing homes is to ensure that they are as insusceptible to burning as possible (e.g., fire resistant building materials, spark arresting vents and rain-gutter guards) and to create defensible space within a 100-foot radius of a structure. Wildland fire policy should fund defensible space, home retrofitting measures and ensure ample personnel are available to discourage and prevent human-caused wildfire ignitions. Ultimately, in order to stabilize and ideally slow global temperature rise, which will increasingly affect how wildfires burn in the future, we also need a comprehensive response to climate change that is based on clean renewable energy and storing more carbon in ecosystems.