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DEAD TREES?
Dead Trees Provide Critical Habitat. They do not Pose the Fire Risk Claimed.
There is a tremendous amount of concern expressed about dead trees by politicians and some fire officials.
Newspaper articles claim that dead oak trees were responsible for the spread of the 2018 Tubbs Fire in Santa Rosa (they weren't).
California's dead tree mapping program shows large numbers of dead trees in the middle of chaparral where there are no trees (see below).
A USFS official claimed during a Governor's Fire/Climate Change Task Force meeting that there was a hole of dead trees in the Sierra National Forest of several thousand acres, with not one living tree in the area (lots of living trees and new saplings are still growing there).
Dead trees are blamed for the wildfire crisis when dead trees have never contributed to a catastrophic fire in California (see map below).
Newspaper articles blame a century of aggressive fire suppression and "forests thick with spindly trees" for southern California wildfires when forests are nowhere near the fires and past fire suppression is not an issue.
What's going on? Why all the extreme warnings about dead trees when nearly all of California's most devastating fires have little to do with forests?
It is likely that the focus on dead trees is more the result of vested logging interests than anything having to do with human safety. Below we examine the issue of trees (dead and otherwise) in both forests and the chaparral.
Dead Trees have next to Nothing to do with Devastating Wildfires
Update with the 2020 wildfires coming soon. But the basic story remains the same - it's not about dead trees.
Dead tree concentrations from the California State Tree Mortality map with the most devastating wildfires in California. With the exception of the Ferguson Fire where a firefighter was killed from a falling tree branch, all of the most devastating wildfires were far from any significant number of dead trees. Additional information about this map can be found in our article, It's About Flammable Homes, Not Forests.
Dead Trees, Bark Beetles, and Questionable Claims
about Forest Density
Despite all the panic-filled claims by fire officials and foresters, tree mortality and density in many of our Western forests have not created an ecological disaster nor have these conditions automatically increased fire risk.
Scientific studies have consistently found that trees killed by drought and or beetles (drought is what weakens the trees to allow for beetle attack) do NOT increase risk or severity of wildfire. The most comprehensive study published in the Proceedings of the National Academy of Sciences concluded, "the annual area burned in the western United States has not increased in direct response to bark beetle activity" (Hart et al. 2015). A study from the University of Montana stated "weakening or eliminating environmental laws to allow more beetle timber harvest treatments is the wrong choice for advancing forest health in the United States" (Six et al. 2014).
Other papers concerning tree mortality, beetles, and logging for "restoration" in our forests: Fire risk and dead trees
"High severity fire was more prevalent in stands with low MPB (mountain pine beetle) mortality due to the higher proportion of live trees (and therefore fine aerial fuels) remaining."Agne, M.C., T. Woolley, and S. Fitzgerald. 2016. Fire severity and cumulative disturbance effects in the post-mountain pine beetle lodgepole pine forests of the Pole Creek Fire. Forest Ecology and Management 366: 73-86.
"While research is ongoing and important questions remain unresolved, to date most available evidence indicates that bark beetle outbreaks do not substantially increase the risk of active crown fire in lodgepole pine (Pinus contorta) and spruce (Picea engelmannii)-fir (Abies spp.) forests under most conditions. Instead, active crown fires in these forest types are primarily contingent on dry conditions rather than variations in stand structure, such as those brought about by outbreaks."Black, S.H., D. Kulakowski, B.R. Noon, D.A. DellaSalla 2013. Do bark beetle outbreaks increase wildfire risks in central U.S. Rocky Mountains? Natural Areas Journal 33 (1): 59-65.
"We found no evidence that pre-fire tree mortality influenced fire severity. These results indicate that widespread removal of dead trees may not effectively reduce higher-severity fire in southern California’s conifer forests."Bond, M.L., D.E. Lee, C.M. Bradley, C.T. Hanson. 2009. Influence of pre-fire tree mortality on fire severity in conifer forests of the San Bernardino Mountains, California. The Open Forest Journal 2: 41-47.
"Our results suggest that mountain pine beetle outbreaks in Greater Yellowstone may reduce the probability of active crown fire in the short term by thinning lodgepole pine canopies."Simard, M., W.H. Romme, J.M. Griffin, M. G. Turner. 2011. Do mountain pine beetle outbreaks change the probability of active crown fire in lodgepole pine forests? Ecological Monographs 81(1): 3-24.
Logging for "restoration"
"The likelihood of thinning treatments and wildfire overlapping in time and space is quite low when the treatment is most effective (less than 20 yrs). In fact, the chance that thinning will influence fire behavior is based on a number of improbable factors..."DellaSala, D.A., and M. Koopman. 2015. Thinning combined with biomass energy production may increase, rather than reduce, greenhouse gas emissions. Geos Institute, Ashland, OR.
"Ecosystems recovering after disturbance can be species-rich early successional environments but their habitat values can be impaired by post-disturbance, management."Lindernmayer, D., S. Thorn, and S. Banks. 2017. Please do not disturb ecosystems further. Nature Ecology & Evolution 1: 1-3. DOI: 10.1038/s41559-016-0031 | www.nature.com/natecolevol
"Though it may seem to some laypersons that a post-fire landscape is a catastrophe, numerous scientific studies tell us that even in the patches where forest fires burn most intensely, the resulting wildlife habitats are among the most ecologically rich and diverse on western forestlands and are essential to support the full range of forest biodiversity."Open Letter to U.S. Senate and President Obama from 285 Scientists Concerned about Post-fire Logging and Logging of Old Forest on Federal Public Lands, November, 2016.
Scientific studies have consistently found that trees killed by drought and or beetles (drought is what weakens the trees to allow for beetle attack) do NOT increase risk or severity of wildfire. The most comprehensive study published in the Proceedings of the National Academy of Sciences concluded, "the annual area burned in the western United States has not increased in direct response to bark beetle activity" (Hart et al. 2015). A study from the University of Montana stated "weakening or eliminating environmental laws to allow more beetle timber harvest treatments is the wrong choice for advancing forest health in the United States" (Six et al. 2014).
Other papers concerning tree mortality, beetles, and logging for "restoration" in our forests: Fire risk and dead trees
"High severity fire was more prevalent in stands with low MPB (mountain pine beetle) mortality due to the higher proportion of live trees (and therefore fine aerial fuels) remaining."Agne, M.C., T. Woolley, and S. Fitzgerald. 2016. Fire severity and cumulative disturbance effects in the post-mountain pine beetle lodgepole pine forests of the Pole Creek Fire. Forest Ecology and Management 366: 73-86.
"While research is ongoing and important questions remain unresolved, to date most available evidence indicates that bark beetle outbreaks do not substantially increase the risk of active crown fire in lodgepole pine (Pinus contorta) and spruce (Picea engelmannii)-fir (Abies spp.) forests under most conditions. Instead, active crown fires in these forest types are primarily contingent on dry conditions rather than variations in stand structure, such as those brought about by outbreaks."Black, S.H., D. Kulakowski, B.R. Noon, D.A. DellaSalla 2013. Do bark beetle outbreaks increase wildfire risks in central U.S. Rocky Mountains? Natural Areas Journal 33 (1): 59-65.
"We found no evidence that pre-fire tree mortality influenced fire severity. These results indicate that widespread removal of dead trees may not effectively reduce higher-severity fire in southern California’s conifer forests."Bond, M.L., D.E. Lee, C.M. Bradley, C.T. Hanson. 2009. Influence of pre-fire tree mortality on fire severity in conifer forests of the San Bernardino Mountains, California. The Open Forest Journal 2: 41-47.
"Our results suggest that mountain pine beetle outbreaks in Greater Yellowstone may reduce the probability of active crown fire in the short term by thinning lodgepole pine canopies."Simard, M., W.H. Romme, J.M. Griffin, M. G. Turner. 2011. Do mountain pine beetle outbreaks change the probability of active crown fire in lodgepole pine forests? Ecological Monographs 81(1): 3-24.
Logging for "restoration"
"The likelihood of thinning treatments and wildfire overlapping in time and space is quite low when the treatment is most effective (less than 20 yrs). In fact, the chance that thinning will influence fire behavior is based on a number of improbable factors..."DellaSala, D.A., and M. Koopman. 2015. Thinning combined with biomass energy production may increase, rather than reduce, greenhouse gas emissions. Geos Institute, Ashland, OR.
"Ecosystems recovering after disturbance can be species-rich early successional environments but their habitat values can be impaired by post-disturbance, management."Lindernmayer, D., S. Thorn, and S. Banks. 2017. Please do not disturb ecosystems further. Nature Ecology & Evolution 1: 1-3. DOI: 10.1038/s41559-016-0031 | www.nature.com/natecolevol
"Though it may seem to some laypersons that a post-fire landscape is a catastrophe, numerous scientific studies tell us that even in the patches where forest fires burn most intensely, the resulting wildlife habitats are among the most ecologically rich and diverse on western forestlands and are essential to support the full range of forest biodiversity."Open Letter to U.S. Senate and President Obama from 285 Scientists Concerned about Post-fire Logging and Logging of Old Forest on Federal Public Lands, November, 2016.
Dead Trees in the Chaparral?
The image above shows the state's Tree Mortality Viewer analysis of an area in the Cleveland National Forest above Corona, California indicating the presence of 15-40 dead trees per acre (see solid red polygon). Using a mid-range estimate of 25 dead trees, the state indicates there are about 12,000 dead trees in the area. The same area outlined in white is enlarged below.
This is a dense chaparral plant community with a few scattered, healthy oaks, big cone Douglas firs, and a few other tree species in canyon areas. No dead trees are present. Field observations have confirmed the disconnect between the state's dead tree map and what is actually on the ground here. Unfortunately, this is not an isolated problem. We have found many areas throughout the state where the state map indicates dead trees where there are none.
Celebrating the Unique Trees of the Chaparral
Rather than worrying about dead trees, let's celebrate some of the special trees that have evolved to survive
the high intensity fires that have shaped the chaparral for millions of years.
The big cone Douglas fir (Pseudotsuga macrocarpa) is typically found in steep canyons surrounded by chaparral. They are one of the few conifers that can resprout and it does so from nearly every branch after a fire.
The gray pine (Pinus sabiniana) is found in central and northern California deeply embedded in the chaparral.
The Tecate cypress (Hesperocyparis forbesii) is endemic to the chaparral in southern California. It is becoming increasingly rare due to human-caused wildfires.
Close up, the big cone Douglas fir looks like a sparse, giant Christmas tree with long, skinny branches.
The Coulter pine (Pinus coulteri) is serotinus when it appears in the chaparral, meaning its cones generally do not open until heated by a fire. In forests, the Coulter pine has cones that open every year.
The Torrey pine (Pinus torreyana) is found in two places on earth - in San Diego and Santa Rosa Island off the coast of Santa Barbara. The individuals on the Island are shorter and more stouter.