Response to Prescribed Burn Oregon Capital Chronicle Article

An article in the Oregon Capital Chronicle focuses on cultural and prescribed burning fuel reduction and how they can preclude large wildfires, such as the 127,000 acre Cedar Creek Fire on the Willamette National Forest. The Cedar Creek fire was a wind-driven blaze that occurred during severe drought. The only thing that brought the blaze under control was a change in weather. On October 27^th, due to temperatures dropping and humidity rising, the progression of fires was halted.

Why is this important? Because all large wildfires are climate and weather-driven events, if you have severe drought, high temperatures, low humidity, and, most importantly, high winds, the result is unstoppable blazes.  This fact is underscored by a review of wildfire acreage charred during the last century. In the early 1900s, we had severe drought (remember the Dust Bowl), and up to 50 million acres of the West were charred by wildfire in a single fire season. Today, if 10 million acres burn, it is considered a “record”.

Then, sometime in the late 1930s, the climate became cooler and moister, and natural climate cooling reduced the number of ignitions and acreage charred. Indeed, during this period, glaciers expanded on the higher peaks of the Cascades. In the late 1980s, climate warming led to more ignitions and higher severity blazes. Nature is what controls wildfire events. In times of cooler weather, such as the period between 1940 and the late 1980s, there are few wildfires of any significance.

An excellent example of how ineffective fuel reductions are when there is extreme fire weather was the Labor Day 2020 Holiday Farm Blaze, driven by extreme winds, ran across miles of clearcuts and other “fuel reductions” on the Willamette National Forest and private commercial timberlands near Eugene, Oregon.

The two images demonstrate how ineffective fuel reductions are in halting a wind driven blazes. The top image shows the fire severity of the Holiday Farm Fire that charred the McKenzie River Valley, Oregon in 2020. Green lightly or no burn, red high severity burn, and yellow mixed severity. The blaze went through an area of extensive clearcuts shown below it in the Google Earth image. The Cougar Reservoir is visible in the lower right hand corner of both images.

If massive clearcuts won’t stop a wind-driven wildfire, then it is delusional to believe a prescribed burn will have any effect. Research by paleoclimate/fire scientists on the influence of human ignitions on plant communities concludes that Indian cultural burns only modified fuels locally—typically around villages and other areas with extensive human presence. 

For example, Cathy Whitlock, who researched the relationship
between climate and ignitions in the Willamette Valley, concluded: “The idea
that Native Americans burned from one end of the valley to the other is not
supported by our data … Most fires seem to have been fairly localized, and
broad changes in fire activity seem to track large-scale variations in climate.”

It is essential to reiterate the scientific consensus that
prescribed burning might work for a very short time (only a few years to a
decade at best) to slow or stop wildfire burning under low to moderate fire
weather conditions; it fails under extreme fire weather. This short-term
influence is a crucial point often overlooked in discussions on wildfire
management.

Another problem that should be acknowledged is that prescribed burn fuel reductions are transitory.

Immediately after a fire, the regrowth of vegetation quickly negates the influence on fuel. Indeed, in many cases, prescribed burning results in more fine fuels like
grasses, small trees, and shrubs, which are the primary fuel components of any
blaze.  If a prescribed burn is to have any chance of curtailing a blaze’s advance, it must be repeated every few years–forever.

The probability that a fire will encounter a prescribe burn or fuel reduction is extremely limited by the long fire rotation of most plant communities in the West. Old growth Douglas fir seen here along the McKenzie River has a fire rotation of hundreds of years. Photo George Wuerthner

The other issue is the extremely small probability that any blaze will encounter a fuel reduction when it might be effective—typically 1-2%. So, everyone suffers from the smoke, and the chance that a prescribed burn will get away and burn considerably more acreage is seldom acknowledged.

A review article that examined 1500 wildfires to determine how fuel reductions
influenced fire severity concluded that fire severity was lower in protected
landscapes like wilderness areas and parks even though they presumably had
higher fuel loadings than areas under “active forest management.”

We have evolutionary evidence that the fire rotation of most plant communities across the West is typically decades to hundreds of years. Many plant communities, like
sagebrush, chaparral, and higher-elevation forests of spruce and fir, have no
adaptations to fire, demonstrating that fire from any source, Indian or natural
ignitions, is infrequent.

The general theme of the article suggests that large, high-severity blazes are “bad,” while low severity contributes to “forest health.” 

However,high-severity blazes and the resulting snag forests are critical to healthy
forest ecosystems. Numerous plants and animals depend on high-severity fires
for their survival.

Massive ice sheets covered North America 20,000-40,000 years ago and precluded colonization by humans. Photo George Wuerthner

Finally, the statement that tribal people have been burning
the land for 20,000-40,000 years is contradicted by the fact almost all of
North America was under giant sheets of ice at the close of the Pleistocene
Glacial period.