Is Reducing Wildfire Fuels Common Sense?

One continuously hears that “common sense” dictates that logging the forest to decrease “fuels” will eliminate or reduce large wildfires.

Common sense also suggests the sun circles the earth, as anyone can quickly determine by watching it rise in the east and set in the west. However, as most of us know, the earth circles the sun despite what common sense might conclude.

Common sense would suggest the sun circles the Earth, afterall it rises in the east and sets in the West. But science tells us otherwise and the Earth circles the sun. Photo George Wuerthner

It’s a similar situation with wildfires. Nearly all the wildfires that capture media and the public’s attention are those burning under “extreme fire weather” conditions.

Wind blows embers far n front of any fireline, a feature known as spotting, making it nearly impossible to stop a wind-driven blaze. View of 1988 burn pattern along the shore of Yellowstone Lake, Yellowstone NP. Photo George Wuerthner

Wind blown embers bunt this home to the foundation. Waldo Canyon Fire, Colorado. Photo George Wuerthner

These circumstances include low humidity, drought, high temperatures, and, most importantly, high winds, transporting embers miles in front of the fireline. Embers, not a wall of flame, ignite most structures. It is the fire weather conditions that determine fire size and severity. I am unaware of any logging project that altered the weather.

Such conditions are relatively rare. Less than 1% of all wildfires burn under such conditions, but extreme fire weather is responsible for 95-99% of all the acreage burned by wildfire annually. Under these conditions, wildfires are often uncontrollable.

Most fires are ignited under less than extreme conditions, typically char only a few acres, and often self-extinguished.

The 2017 Thomas Fire near Santa Barbara burned through and over numerous fire breaks including Coast HIghway 101. The only fuel reduction that halted the westward fire’s spread was the Pacific Ocean. Photo George Wuerthner

Hence, the very wildfires thinning and logging proponents claim they hope to contain or moderate are the ones that rarely respond to fuel reductions.

The 2020 wind driven Holiday Farm Fire in Oregon burned through even areas of extensive clearcuts. If clearcuts don’t halt a wildfire, why would anyone believe that thinning only some of the trees would be effective? Photo George Wuerthner

While fuel reductions might seem like common sense, there are sidebars to consider. Logging opens up the forest canopy, leading to less shade and more sun on the forest floor, hence drying, which enhances one factor in fire spread.

Thinning can open the canopy allowing fuels to dry and wind to penetrate. Plus often results in more “fuel” on the ground. Newberry Crater NM, Oregon. Photo George Wuerthner

Opening up the canopy can also promote the growth of fine fuels like grass, shrubs, and trees, which are more easily ignited than a tree bole, thus contributing to a more significant wildfire threat.

Removing trees also permits greater wind penetration, boosting wind penetration, which increases fire expansion.

Logging and thinning remove wood fiber from the forest, reducing overall carbon storage. Photo George Wuerthner

A further consideration is that logging removes trees from the forest, diminishing carbon storage and wildlife habitat.

Like the idea that the sun circles the earth, logging to reduce fuels may seem to make “common sense” but may have the opposite effect.