Several recent contributors to The News-Review have shared an opinion that local federal BLM and Forest Service lands are being mismanaged by allowing fuel to build up in old-growth forests. Without evidence, they claim this causes wildfires to burn more severely, endangering adjacent homes and private plantations.
A number of recent peer-reviewed studies at local, regional and international scales indicate quite the opposite: forests with more old-growth and fewer plantations are more fire-resilient than lands dominated by even-aged plantations with dense, continuous fuels.
Even though there is typically more biomass in a native forest, the structure of their fuels makes plantations burn more severely. Old-growth forests are cool and moist, providing double the stream flows of plantations. Large, widely spaced trees with uneven heights, thick bark, and separated crowns are highly resistant to wildfires. These older forests commonly exist as islands on public lands that were also havily clearcut and replanted in rows a few paces apart beginning in the middle of the last century. Stand on any viewpoint in the public/private BLM “checkerboard” and 60-80% of the what you see will be carpets of plantations.
The facts unequivocally support the common-sense conclusion that dense, flammable plantations put the last stands of remaining old growth forests at greater risk, not the other way around.
In 2013, a swarm of dry lightning struck in the Cow Creek drainage, with the strikes distributed evenly across federal and private land. The Douglas Complex fire burned through nearly 20,000 acres of public and private timberlands. Heat patterns from satellite images revealed higher intensity fires in plantations even though the public’s old growth contained more biomass. Subsequent analysis confirmed that observation: weather was found to be the biggest driver of tree mortality, but “…intensive plantation forestry characterized by young forests and spatially homogenized fuel, rather than pre-fire biomass, were significant drivers of wildfire severity.”
An analysis of the 2020 Archie Creek Fire again found that after weather, forest management is the most important factor influencing fire severity.
Winds were unusually high during a heat event as the fires were sparked at many locations along a powerline. Nearly ¾ of the 131,000-acre fire area burned severely in the first day, with public lands faring slightly better (75.3%) than private (80.7%). But after the wind event, “… there was a sharp decline in high severity fire and we observed an increase in mixed-severity mosaics… private lands burned at significantly higher severities than federal lands.”
All of the 2020 Labor Day Fires mirrored Archie Creek: “Early-seral forests [plantations] primarily concentrated on private lands, burned more severely than their older and taller counterparts, over the entire megafire event regardless of topography,” and “Under high fuel aridity but light winds, young tands composed of small trees, found primarily on private lands, exhibited a much lower survival rate than older stands composed of medium to large trees, found primarily on federal lands.” The Oregon Forest Resources Institute also reports that high-severity fires were most common on “Large Private” lands followed by BLM and the USFS lands.
At the regional scale, an analysis of 23.5 million acres of western conifer forest found that burn severity tended to be lower in areas with more ecological protections (less intensive management), after accounting for topographic and climatic conditions. International studies are in close agreement: fire risk increases with intensive forest management.
Another common narrative implies that wildfires tend to start on “poorly managed” public lands and spread to nearby communities. A recent study of western US wildfires refutes this: “…cross-boundary fires were primarily caused by humans on private lands… Public lands managed by the US Forest Servie were not the primary source of fires that destroyed the most structures.”
Other messaging suggests that if public timber is not salvaged, burned forests will be more flammable and will not regenerate as well as logged and replanted sites. On the contrary, black trees don’t carry fires and they don’t impede forest regrowth.
A study conducted after the nearby 2002 Biscuit fire reburned parts of the 1987 Silver fire documented that salvage-logged and replanted areas “…burned more severely than comparable unmanaged areas, suggesting that fuel conditions in conifer plantations can increase fire severity despite removal of large woody fuels.” Another found that, “Natural conifer regeneration was abundant after the high-severity fire. Postfire logging reduced median regeneration density by 71%, significantly increased downed woody fuels, and thus increased short-term fire risk… Postfire logging can be counterproductive to the goals of forest regeneration and fuel reduction.”
We can all gree: no one wants to see more megafires. But before we can start talking about solutions, we all have to recognize the problem. Science and common sense agree — the forestry practices of the last century combined with a changing climate and increasing human caused ignitions means we will either need to get used to smokey summers or change the way we treat our forests.
Ken Carloni has studied wildfire for over 30 years and earned his doctorate researching historic fire patterns in SW Oregon. He currently consults on ecosystem management and biochar production. A fully referenced version of this article can be found at umpquawatersheds.org.