Community Coastal Column

Industrial Timber Production Increases Fire Risk (And Other ings the Gov’t Doesn’t Want You to Know)

Tom Wheeler, EPIC

Fire severity—how impactful a re is to the natural environment—escapes easy explanation. ere is no one thing that determines re severity, rather a variety of factors in uence it. But looking across millions of acres of burned land in the West, one thing bears true: res burned with less intensity on lands that had the highest protections from logging. Why is this?

Wildland re behavior is sometimes explained using the re behavior triangle, with fuels, weather/ climate and topography all interacting with each other to in uence how fast and how hot a re will burn. Logging a ects two sides of this triangle: fuels and weather/climate.

Logging obviously removes some “fuels” as trees and brush are combustible. But this simple truth masks some of the important complexity. How fuels are distributed within an area, both vertically and horizontally, together with their type (fast burning “ ne” fuels, like leaves or twigs vs. longburning “heavy fuels, like logs, which may smolder longer but don’t typically are up) and moisture all impact re behavior. While logging removes some fuels, it typically removes the heavy fuels while redistributing ner fuels—the logging “slash” of limbs, tops, branches and needles—from standing trees to the ground. is can leave “jackpots” of fuels that can cause sudden and aggressive are ups.

Clearcut logging introduces yet another issue: uniform crown structure. As clearcutting produces even-aged forests, the tops or “crowns” of these trees will be approximately the same height. And given the high density of trees typically replanted after a clearcut, these are going to produce an interlocking, dense crown. If re jumps to the crown, the fuel continuity provided by this uniform crown structure can quickly cause fast-moving and highly impactful res.

Logging also impacts the likelihood of tree survival. Large, old trees generally are more resilient to re. eir thick bark helps insulate the trunk from damage and tall branches make res jumping from the forest oor to the crown more di cult. Of course, logging can both remove big resilient trees and make their future development more di cult, as they are logged before they can reach a nice, ripe age.

Weather and climate are also extremely important to understanding re behavior. Logging a ects both weather and climate. Cutting shade-producing trees can both increase in-forest temperatures and reduce moisture in the forest, producing a parched microclimate. inning trees increases in-forest wind speed, which can both create a drier forest through enhanced evaporation rates as well as fanning the ames during a re to produce a greater intensity.

While it is clear that logging can impact sitespecific conditions that intensify fire behavior, logging also is a major source of greenhouse gas emissions. Climate change serves to exacerbate wild res by broadly changing weather and climate conditions. Logging releases carbon that was once locked up in a forest. While some carbon is stored

Slash piles can leave “jackpots” of fuels that can cause sudden and aggressive are-ups. Photo credit: Art Mielke, Mendocino Trail Stewards. in forest products, like paper or lumber, the majority of carbon in a tree becomes susceptible to release as greenhouse gases soon after that tree is logged. Only a small percentage of a tree ever becomes a stable forest product; the majority of the rest is typically burned or decomposes along the way, either in slash piles in the forest or as “mill waste” burned to produce heat or energy. By taking carbon that was safely sequestered for many decades and releasing it suddenly in a quick pulse, logging signi cantly contributes to greenhouse gas emissions—so much so that researchers now report it is the largest source of greenhouse gas emissions in Oregon (and presumably is the largest in the timber-producing areas of California as well).