Comment Log Display

Note: Your submission system does not function properly and would
not accept my comments as written, with figures and photos
included. While the text of my comments are below, the figures are
found in the additional attached comments (our comments on the
North Fork logging proposal), fyi. Chad

30 September 2024

Re: Comments to CARB due Sept. 30 re: Malcolm North presentation to
Expert Advisory Committee 9/12 Meeting - AB 1757 discussion

Submitted via:
https://www.arb.ca.gov/lispub/comm/iframe_bcsubform.php?listname=eiarecirc_lcfs2024&comm_period=A

To Whom It May Concern, 

On behalf of the John Muir Project of Earth Island Institute, I am
submitting these expert scientific comments to address some highly
misleading and scientifically inaccurate statements, promoting
widespread logging under the guises of thinning, fuel reduction,
and restoration/resilience, by U.S. Forest Service scientist
Malcolm North. 

The North et al. (2022) Article Has Been Scientifically Discredited
and Has Been Found to Represent a "Falsification of the Scientific
Record"; "Thinning" Kills Far More Trees Than It Prevents from
Being Killed. 

The Forest Service improperly relies on its North et al. (2022)
study, which has been discredited and has been found to represent a
"falsification of the scientific record" (Baker et al. 2023). 

First, North et al. (2022) relies on previous studies by Collins
and Stephens, which reported that there were only 20 to 30 trees
per acre in historical Sierra Nevada forests, based on circa 1911
Forest Service field surveys. However, as we found in Baker et al.
(2018), the Collins and Stephens work omitted the small-tree data
in those historical datasets and failed to use correction factors
that the Forest Service itself, a century ago, repeatedly stated
were needed to avoid severe underestimations of forest density. The
surveys were based on visually estimated distance from the transect
line, but surveyors consistently overestimated distance (e.g., they
would see 30 or 40 feet to their left and right but would assume
they were seeing 66 feet left and right). Moreover, small trees in
historical Forest Service survey data were omitted in recent Forest
Service studies. These factors caused a huge underestimation of
forest density. When we included all of the improperly omitted
data, we found that historical mixed-conifer forests of the Sierra
Nevada were 7 times denser, in terms of trees per acre, than the
Forest Service erroneously claimed, and historical ponderosa pine
forests were 17 times denser than recent, and now discredited,
Forest Service studies falsely claimed, as we reported in Baker et
al. (2018). Our findings in Baker et al. (2018) are uncontested. 
 
Second, North et al. (2022) misleadingly claimed that "current"
forests have 150 to 200 trees per acre, but inexplicably used data
from 2011 to represent supposed "current" conditions, and failed to
mention that over 90% of their study areas have burned in
mixed-intensity wildfires since 2011, and that a large portion of
the live trees that existed a decade ago are now snags and downed
logs. 

The bottom line is that North et al. (2022) severely underreported
historical forest density by using previous historical density
estimates that have been discredited and superseded, and
overreported current live tree forest density by using 2011 as
their "current" condition, despite the fact that fire and drought
since 2011 have dramatically reduced live tree density in their
study areas. 

Further, studies that have claimed success of such projects on
reducing bark beetle mortality generally do not consider the
treatment-caused mortality when considering the concept of a
successful treatment. For instance, Fettig et al (2012) examined
the effect on bark beetle-induced tree mortality of various levels
of thinning in comparison to unthinned areas in mixed-conifer
forests in the Sierra Nevada. While they stated that "[i]n the
present study, bark beetle-caused tree mortality was relatively low
the decade after thinning, never reaching a level that would be
considered epidemic for either P. jeffreyi or P. ponderosa..." the
authors did not consider the initial mortality event caused by the
thinning treatment itself. Their measure of success was whether the
level of tree mortality in thinned stands was less than that in the
unthinned stands, but apparently mortality was only significant to
success if caused by bark beetles. When analyzing the data they
present, it is actually quite simple to glean that the overall
mortality (i.e. mortality from thinning plus mortality from
subsequent bark beetles) in the three thinning treatments was
substantial (109 - 289 trees killed per hectare on average)
compared to the overall mortality in the unthinned stands
(approximately 13 trees killed per hectare on average). Granted,
the number of trees killed by bark beetles was slightly lower in
the thinning units (3 - 11 trees killed per hectare on average)
compared to the unthinned stand (13 trees killed per hectare on
average), but this pales in comparison to overall number of trees
killed due to the thinning itself (see Figure 1). Another way to
view this is, approximately 289 trees per hectare were killed in
the most intensive treatment by the thinning itself in order to
prevent 10 trees from being killed in the future by bark beetles. 



 
Data taken from Fettig et al. (2012), showing cumulative tree
mortality from thinning and bark beetles combined. Note that
thinning killed vastly more trees than it prevented from being
killed, and removed vastly more carbon from the forests in the
process. 

Six et al. (2014) notes a similar pattern: 
"Although more trees were killed overall in control units during
the outbreak, all controls still retained a greater number of
residual mature trees than did thinned stands as they entered the
post-outbreak phase." 
And a separate study in ponderosa pine forests in the Black Hills
similarly demonstrated that far more trees were killed through the
actual thinning process than through a subsequent bark beetle
outbreak that was more severe than that experienced in the study by
Fettig et al. (2012). Negron et al (2017) examined stands in which
the overall mortality (again, mortality caused by thinning plus
mortality caused by bark beetles) was 242.6 trees killed per acre
on average in thinned stands compared to 87.7 trees killed per acre
in unthinned stands. As with other similar studies, the treatment
was the primary source of mortality in the stand rather than bark
beetles. By the end of the outbreak, not only were there more trees
in the unthinned stands (203.2 trees per acre on average) compared
to the thinned stands (55 trees per acre on average) as well as
more basal area (which could be considered a proxy for both biomass
and carbon storage; 67.8 square fee per acre compared to 32.3
square feet per acre). 
In Sierra Nevada mixed-conifer and ponderosa pine forests after the
major drought occurring approximately 2012-2017, Restaino et al.
(2019) reported, in Figures 3 and 4, mixed effects of increasing
forest basal area on tree mortality from drought and native bark
beetles, with no clear relationship. Restaino et al. (2019), in
Figure 5, reported that thinned forests had approximately the same
or higher tree mortality from drought/beetles compared to unthinned
forests for three of the four conifer species studied. Only one of
the four conifer species studied, ponderosa pine, had slightly
lower probability of mortality in thinned forests than in unthinned
forests, but the difference was only 15% on average, while Figure
2a of the study showed that thinning itself killed about 35% of the
forest basal area before the drought occurred; thus thinning once
again killed more trees than it prevented from being killed, even
for the one conifer species out of four for which the thinned areas
had somewhat lower probability of tree mortality. 
North et al. (2022) fails to divulge or disclose the fact that
mechanical thinning, conducted ostensibly to reduce stand densities
and reduce competition-related tree mortality, kills far more trees
than it prevents from being killed. 

Moreover, Baker and Hanson (2022) establish that mechanical
thinning kills significantly more trees than it prevents from being
killed, when tree mortality from thinning and tree mortality from
subsequent wildfire are both taken into account. 

Further, the best available scientific evidence, and most
comprehensive, finds that forest stands with higher levels of snags
(standing dead trees) from drought and native bark beetles do not
increase wildfire behavior and often have lower wildfire
intensities (Hart et al. 2015, Meigs et al. 2016, Hart and Preston
2020). Moreover, the Forest Service's own research documented the
fact that the agency's annual aerial tree mortality surveys have
been exaggerating yearly tree mortality profoundly--by tenfold to
twentyfold (Slaton et al. 2021). The Forest Service and its
scientists have known this for over three years, so why are the
agency's scientists continuing to publicly promote the false and
utterly discredited claim that nearly 200 million trees have died
due to drought and native bark beetles in California's forests in
recent years? 

Decades of Science by the U.S. Forest Service and U.S. National
Parks Service Clearly Establish that (a) Protecting Communities
from Wildfires Can Only Effectively Be Done in the Communities
Themselves, and (b) There Is No Need to Remove Trees Before
Burning--Either Controlled Burns or Prescribed Natural Fires. 

The only effective way to protect human communities from wildland
fire is to conduct/support: (a) defensible space pruning within 100
feet or less from homes and other human structures, along with
providing information to homeowners about simple steps they can
take to make their homes more fireproof (e.g., ember-proof vents)
and implement effective wildfire evacuation planning, and (b)
prescribed burning and managed wildfire, with no prior tree
removal, in the remainder of the Project area. There is no need to
remove any trees, even small ones, before conducting such
burning--entities engaged in controlled burns and prescribed
natural fire activities need only conduct and allow such activities
during milder fire weather. For example, the EA (Table 3.8-1) and
Responses to Comments (p. 37) for the Plumas National Forest's
"Community Protection Project - Central and Western Slope" Project
admitted that prescribed fire can be applied without prior
thinning, and that prescribed fire alone is far less expensive than
mechanical thinning plus slash burning. As we explain below,
serious matters of public safety are at issue here, and the
landscape-level logging promoted by the U.S. Forest Service,
through Dr. North, will increase, not decrease, threats to
communities from wildfires. 


The only effective way to protect homes from fire is home-hardening
and defensible space pruning within about 100 feet of homes or
less.

Cohen, J.D. (U.S. Forest Service). 2000. Preventing disaster: home
ignitability in the wildland-urban interface. Journal of Forestry
98: 15-21. 

The only relevant zone to protect homes from wildland fire is
within approximately 100 feet or less from each home--not out in
wildland forests. 


Gibbons P, van Bommel L, Gill MA, Cary GJ, Driscoll DA, Bradstock
RA, Knight E, Moritz MA, Stephens SL, Lindenmayer DB (2012) Land
management practices associated with house loss in wildfires. PLoS
ONE 7: Article e29212. 

Defensible space pruning within approximately 100 feet from homes
was effective at protecting homes from wildfires, while vegetation
management in remote wildlands was not. 


Syphard, A.D., T.J. Brennan, and J.E. Keeley. 2014. The role of
defensible space for residential structure protection during
wildfires. Intl. J. Wildland Fire 23: 1165-1175.

Vegetation management and removal beyond approximately 100 feet
from homes provides no additional benefit in terms of protecting
homes from wildfires. 


Tree removal is not necessary prior to conducting prescribed fire
or prescribed natural fire (managed wildfire).

Decades of scientific studies have proven that, even in the densest
forests that have not experienced fire in many decades, prescribed
fire can be applied without prior tree removal, as demonstrated in
the following studies: 
Knapp EE, Keeley JE, Ballenger EA, Brennan TJ. 2005. Fuel reduction
and coarse woody debris dynamics with early season and late season
prescribed fire in a Sierra Nevada mixed conifer forest. Forest
Ecology and Management 208: 383-397. 
Knapp, E.E., and Keeley, J.E. 2006. Heterogeneity in fire severity
within early season and late season prescribed burns in a
mixed-conifer forest. Int. J. Wildland Fire 15: 37-45. 
Knapp, E.E., Schwilk, D.W., Kane, J.M., Keeley, J.E., 2007. Role of
burning on initial understory vegetation response to prescribed
fire in a mixed conifer forest. Canadian Journal of Forest Research
37: 11-22. 
van Mantgem, P.J., A.C. Caprio, N.L. Stephenson, and A.J. Das.
2016. Does prescribed fire promote resistance to drought in low
elevation forests of the Sierra Nevada, California, USA? Fire
Ecology 12: 13-25.
van Mantgem, P.J., N.L. Stephenson, J.J. Battles, E.K. Knapp, and
J.E. Keeley. 2011. Long-term effects of prescribed fire on mixed
conifer forest structure in the Sierra Nevada, California. Forest
Ecology and Management 261: 989−994.
Stephens, S.L., et al. 2021. Fire, water, and biodiversity in the
Sierra Nevada: a possible triple win. Environmental Research
Communications 3: Article 081004. 

Previous mechanical thinning and post-fire logging was wildly
ineffective and counter-productive as a wildfire management and
community protection approach. 

The images below, from the Washington Post, show the devastation of
the town of Greenville, after the Dixie fire swept up from the
southwest, moving rapidly northeast through vast areas that had
been mechanically thinned, before destroying most of the towns of
Greenville and Canyondam, along with the smaller town of Indian
Falls. 

 

 

 

 


The images below, from Google Earth, show numerous large areas of
pre-fire mechanical thinning and earlier post-fire logging (after
the 2012 Chips fire around Butt Valley Reservoir) on the Plumas
National Forest, southwest, south, and southeast of the Greenville,
Canyondam, and Indian Falls areas, through which the Dixie fire
swept before destroying most of the homes and businesses. For each
location a pair of images is shown--one after mechanical thinning
but before the Dixie fire, and the other after the Dixie fire. GPS
coordinates of the imagery locations are shown at the bottom right
margin of each. Most of the mechanically thinned and post-fire
logged forests burned at high intensity, as the post-fire images
show. 

The images below represent all areas of mechanical thinning and/or
post-fire logging of any significant size that could be identified
as occurring within 15 years or so prior to the 2021 Dixie fire,
and which were within the path of the fire as it approached
Greenville, Canyondam, and Indian Falls. As the images show, the
Dixie fire burned mostly or entirely at high intensity through all
such areas. For spatial context, each of these images shows an area
that is several thousand acres in size. 












 

Dixie fire perimeter map showing the area on August 7, 2021,
immediately after the fire, moving from the southwest to the
northeast, destroyed Greenville and Canyondam. The map is from the
inter-agency wildfire site, Inciweb: https://inciweb.wildfire.gov 







Image Pair #1: Extensive previous post-fire logging on the Plumas
National Forest, northeast of Butt Valley Reservoir, and a short
distance southwest of Canyondam. The first image is from July 2,
2017, after post-fire logging, and the second is from August 7,
2021, just one day after the Dixie fire burned through this area
and destroyed Canyondam. 

 

 



Image Pair #2: A large area that was mechanically thinned south of
Canyondam. The first image is from May 24, 2009, after thinning,
and the second image is from July 7, 2022 (note the almost total
absence of live, green trees remaining in the thinned areas after
the Dixie fire). 

 


 

Image Pair #3: Mechanical thinning on the Plumas National Forest,
south of Indian Falls. The first image is from May 24, 2009, after
thinning, and the second is from July 7, 2022, after the Dixie
fire. Note that nearly all of the thinned forest burned at high
intensity, with 100% tree mortality in most areas. 

 

 

Image Pair #4: Mechanical thinning south of Greenville on the
Plumas National Forest. The first image is from May 24, 2009. The
second is from July 7, 2022, showing almost complete high-intensity
fire effects in the thinned area. 

 

 

Image Pair #5: Postfire logging and mechanical thinning west of
Greenville and south of Canyondam on the Plumas National Forest.
The first image is from May 24, 2009, and the second is from July
7, 2022, after the Dixie fire. Once again, note that the thinned
area is heavily dominated by high-intensity fire. 

 

 


Image Pair #6: Mechanical thinning on private timberlands south of
Greenville. The first image is from May 24, 2009, and the second is
from July 7, 2022, after the Dixie fire, with the thinned areas
heavily dominated by high-intensity fire. 

 

 
 

The approach promoted by the Forest Service is the same approach
that the agency has pursued for many years, except now the Forest
Service is promoting it on an even bigger scale. In brief, it
involves mechanical thinning and post-fire logging of vast forest
areas distant from communities based on the claim that this will
either directly stop fires from reaching towns or indirectly stop
fires by making fires burn much more slowly and so much less
intensely that fire suppression crews can easily halt the fire
before it reaches a community. This approach is a dangerous, proven
failure, as we have seen in Paradise (Camp fire of 2018),
Greenville (Dixie fire of 2021), Grizzly Flats (Caldor fire of
2021), and Berry Creek and Feather Falls (North Complex fire of
2020), among others. Please see the maps below showing large areas
of thinning and other so-called fuel-reduction logging around towns
that were largely destroyed by the Camp fire, Dixie fire, and
Caldor fire, respectively. In stark contrast, defensible space
pruning immediately adjacent to homes is a consistent success, as
we saw in Meyers and South Lake Tahoe in the Caldor fire (map
below). 

 

 

 

 



 
Map from Wildfire Today, showing the Caldor fire racing right
through "thinning" units in wildlands but stopping at or
immediately adjacent to private property boundaries, where
defensible space pruning had been conducted on private lands and a
short distance on to the National Forest. Map accessed here. Black
ovals have been added to show where the fire stopped in defensible
space areas adjacent to homes. 

The fire effects to the forest and adjacent communities due to
widespread mechanical thinning are serious, given the potential for
"thinning" and other logging to increase, not decrease, fire
severity, based on science submitted here, and as recognized by the
Ninth Circuit Court of Appeals in the 2020 BARK v. U.S. Forest
Service case
(https://scholar.google.com/scholar_case?case=8163889612711152072&q=BARK+v+forest+service&hl=en&as_sdt=2006).
The Ninth Circuit's reasoning is included here:

First, the effects of the Project are highly controversial and
uncertain, thus mandating the creation of an EIS. See 40 C.F.R. §
1508.27(b)(4) & (5) (listing relevant factors for whether an EIS is
required, including if the project's effects are "highly
controversial" and "highly uncertain"). The stated primary purpose
of the CCR Project is to reduce the risk of wildfires and promote
safe fire-suppression activities, but Appellants identify
considerable scientific evidence showing that variable density
thinning will not achieve this purpose. Considering both context
and intensity, as required by 40 C.F.R. § 1508.27, this evidence
raises substantial questions about the Project's environmental
impact, and an EIS is required. See, e.g., Blackwood, 161 F.3d at
1212; Native Ecosystems Council, 428 F.3d at 1238-39.
"A project is `highly controversial' if there is a `substantial
dispute [about] the size, nature, or effect of the major Federal
action rather than the existence of opposition to a use.'" Native
Ecosystems Council, 428 F.3d at 1240 (alteration in original)
(quoting Blackwood, 161 F.3d at 1212). "A substantial dispute
exists when evidence ... casts serious doubt upon the
reasonableness of an agency's conclusions." In Def. of Animals, 751
F.3d at 1069 (quoting Babbitt, 241 F.3d at 736). "[M]ere opposition
alone is insufficient to support a finding of controversy."
WildEarth Guardians v. Provencio, 923 F.3d 655, 673 (9th Cir.
2019).
The EA explained that the CCR Project will use "variable density
thinning" to address wildfire concerns. "In variable density
thinning, selected trees of all sizes ... would be removed." This
process would assertedly make the treated areas "more resilient to
perturbations such as ... large-scale high-intensity fire
occurrence because of the reductions in total stand density."
Variable density thinning will occur in the entire Project area.
Substantial expert opinion presented by the Appellants during the
administrative process disputes the USFS's conclusion that thinning
is helpful for fire suppression and safety. For example, Oregon
Wild pointed out in its EA comments that "[f]uel treatments have a
modest effect on fire behavior, and could even make fire worse
instead of better." It averred that removing mature trees is
especially likely to have a net negative effect on fire
suppression. Importantly, the organization pointed to expert
studies and research reviews that support this assertion.
Bark also raised this issue: "It is becoming more and more commonly
accepted that reducing fuels does not consistently prevent large
forest fires, and seldom significantly 871*871 reduces the outcome
of these large fires," citing an article from Forest Ecology and
Management. Bark also directed the USFS to a recent study published
in The Open Forest Science Journal, which concluded that fuel
treatments are unlikely to reduce fire severity and consequent
impacts, because often the treated area is not affected by fire
before the fuels return to normal levels. Bark further noted that,
while "Bark discussed [during the scoping process] the studies that
have found that fuel reduction may actually exacerbate fire
severity in some cases as such projects leave behind combustible
slash, open the forest canopy to create more ground-level biomass,
and increase solar radiation which dries out the understory[,]
[t]he EA did not discuss this information."
Oregon Wild also pointed out in its EA comments that fuel reduction
does not necessarily suppress fire. Indeed, it asserted that
"[s]ome fuel can actually help reduce fire, such as deciduous
hardwoods that act as heat sinks (under some conditions), and dense
canopy fuels that keep the forest cool and moist and help suppress
the growth of surface and ladder fuels...." Oregon Wild cited more
than ten expert sources supporting this view. Importantly, even the
Fuels Specialist Report produced by the USFS itself noted that
"reducing canopy cover can also have the effect of increasing [a
fire's rate of spread] by allowing solar radiation to dry surface
fuels, allowing finer fuels to grow on ... the forest floor, and
reducing the impact of sheltering from wind the canopy provides."
The effects analysis in the EA did not engage with the considerable
contrary scientific and expert opinion; it instead drew general
conclusions such as that "[t]here are no negative effects to fuels
from the Proposed Action treatments." Appellants thus have shown a
substantial dispute about the effect of variable density thinning
on fire suppression. Although it is not our role to assess the
merits of whether variable density thinning is indeed effective in
the project area to prevent fires, or to take sides in a battle of
the experts, see Greenpeace Action v. Franklin, 14 F.3d 1324, 1333
(9th Cir. 1992), NEPA requires agencies to consider all important
aspects of a problem. See WildEarth Guardians, 759 F.3d at 1069-70.
Throughout the USFS's investigative process, Appellants pointed to
numerous expert sources concluding that thinning activities do not
improve fire outcomes. In its responses to these comments and in
its finding of no significant impact, the USFS reiterated its
conclusions about vegetation management but did not engage with the
substantial body of research cited by Appellants. This dispute is
of substantial consequence because variable density thinning is
planned in the entire Project area, and fire management is a
crucial issue that has wide-ranging ecological impacts and affects
human life. When one factor alone raises "substantial questions"
about whether an agency action will have a significant
environmental effect, an EIS is warranted. See Ocean Advocates v.
U.S. Army Corps of Eng'rs, 402 F.3d 846, 865 (9th Cir. 2005) ("We
have held that one of [the NEPA intensity] factors may be
sufficient to require preparation of an EIS in appropriate
circumstances."). Thus, the USFS's decision not to prepare an EIS
was arbitrary and capricious. See Blackwood, 161 F.3d at 1213
(holding that conflicting evidence on the effects of ecological
intervention in post-fire landscapes made a proposed project highly
uncertain, thus requiring an EIS).

We note that describing mixed-conifer and ponderosa pine forest as
having frequent-fire low-severity regimes is outdated and
misleading, as it is based on the now-discredited notion that fire
return intervals from fire-scar studies are an accurate method to
assess historical fire frequencies. Far more detailed and
comprehensive analyses have determined that historical fire
frequencies in dry forests of the western U.S., such as ponderosa
pine and dry mixed-conifer forests, were about 39 years on average
(e.g., Baker 2017), and actual fire frequencies (fire rotation)
were about 4 times longer than the misleading fire return interval
concept suggested (Crompton et al. 2022 Table 1). 

What about the effect of mechanical thinning on wildfire severity
in mixed-conifer and ponderosa pine forests? The Forest Service's
own scientists (Lesmeister et al. 2021) recently conducted a
massive, landmark 30-year study--a substantial portion of which was
conducted in such forests--and found that, in these forest types
(most frequent fire regime), the densest forests with the highest
biomass, highest canopy cover, and highest tree densities, on
average had lower wildfire severities when fires occurred when
compared to more open, lower-density forests resulting from
mechanical thinning and other logging operations (see Figure 4b
from Lesmeister et al. 2021 below). The Forest Service scientists
concluded that more open forests with lower biomass had higher fire
severity, because the type of open, lower-biomass forests resulting
from thinning and other logging activities have "hotter, drier, and
windier microclimates, and those conditions decrease dramatically
over relatively short distances into the interior of older forests
with multi-layer canopies and high tree density..."

Notably, Lesmeister et al. (2021) made the same finding in their
analysis of more mesic forests, including mesic mixed-conifer
forests. 
Other Forest Service scientists, in Lydersen et al. (2014),
reported the following finding in the 257,000-acre Rim fire of
2013: 

"Density of small to intermediate size trees (20-40 cm dbh in the
analysis with all plots and both 40-60 cm and 60-80 cm dbh in the
analysis excluding plots burned on a plume-dominated day) were also
related to Rim Fire severity, with plots with a greater small tree
density tending to burn with lower severity."

The very largest scientific analysis ever conducted in dry forests
on the subject of tree removal and wildfire severity, Bradley et
al. (2016), found that forests completely protected from tree
removal had the lowest fire severity, while forests with some
limited tree removal allowed had higher levels of fire severity,
and forests with the fewest environmental protections and the most
tree removal had the highest fire severity. The authors concluded
the following: 

"We found forests with higher levels of protection [from tree
removal] had lower severity values even though they are generally
identified as having the highest overall levels of biomass and fuel
loading. Our results suggest a need to reconsider current overly
simplistic assumptions about the relationship between forest
protection and fire severity in fire management and policy." 

Hanson (2021) made similar findings in dry forests in the
approximately 380,000-acre Creek fire of 2020 in the southern
Sierra Nevada, reporting that, based on the Forest Service's own
data, forests with previous logging under the rubric of "fuel
reduction"--specifically, mechanical thinning and post-fire
logging--had overall higher fire severity than unmanaged forests. 


More recently, scientists have begun looking at another key
question regarding mechanical thinning and wildfire severity in dry
forests, related to overall combined tree mortality from thinning
itself and subsequent wildfire. These studies have consistently
found that mechanical thinning kills more trees than it prevents
from being killed in mature and old dry forests, including Baker
and Hanson (2022) (pertaining to the Caldor fire of 2021 in the
northern Sierra Nevada), and DellaSala et al. (2022) (pertaining to
the Wallow fire of 2011 in Arizona). Baker and Hanson (2022)
explained why some studies have erroneously reported that
mechanical thinning is effective as a wildfire management approach:


"Despite controversy regarding thinning, there is a body of
scientific literature that suggests commercial thinning should be
scaled up across western US forest landscapes as a wildfire
management strategy. This raises an important question: what
accounts for the discrepancy on this issue in the scientific
literature? We believe several factors are likely to largely
explain this discrepancy. First and foremost, because most previous
research has not accounted for tree mortality from thinning itself,
prior to the wildfire-related mortality, such research has
underreported tree mortality in commercial thinning areas relative
to unthinned forests. Second, some prior studies have not
controlled for vegetation type, which can lead to a mismatch when
comparing severity in thinned areas to the rest of the fire area
given that thinning necessarily occurs in conifer forests but
unthinned areas can include large expanses of non-conifer
vegetation types that burn almost exclusively at high severity,
such as grasslands and chaparral. Third, some research reporting
effectiveness of commercial thinning in terms of reducing fire
severity has been based on the subjective location of comparison
sample points between thinned and adjacent unthinned forests.
Fourth, reported results have often been based on theoretical
models, which subsequent research has found to overestimate the
effectiveness of thinning. Last, several case studies draw
conclusions about the effectiveness of thinning as a wildfire
management strategy when the results of those studies do not
support such a conclusion, as reviewed in DellaSala et al. (2022)."
(internal citations omitted)

Finally, with regard to the common misconception that mature and
old-growth stands are "overgrown", and have too many smaller trees
relative to historical forests, Baker et al. (2023) meticulously
documented the fact that this notion stems from a pattern of
scientific omissions in studies funded by the Forest Service. This
pattern of omissions of peer-reviewed, published reply articles,
which refuted and discredited U.S. Forest Service response
articles, created a "falsification" of the scientific record
regarding historical forest density and fire regimes. The corrected
record shows that historical forests were much denser on average
than assumed by the Forest Service and were shaped by
mixed-severity fire, not merely low-severity fire. 

A large and growing body of scientific evidence and opinion
concludes that thinning and post-fire logging in wildlands,
conducted under the guise of fuel reduction and fire breaks, is an
ineffective and counterproductive way to protect communities, and
it tends to make wildfires spread faster and often more intensely
toward towns, putting nearby communities at greater risk.

Calkin, D.E., Barrett, K., Cohen, J.D., Finney, M.A., Pyne, S.J.,
and Quarles, S.L. (co-authored by U.S. Forest Service). 2023.
Wildland-urban fire disasters aren't actually a wildfire problem.
Proceedings of the National Academy of Sciences of the United
States of America. 120: e2315797120. 

"The best way to make existing wildfire-vulnerable developments
ignition resistant is to work within the limited area of the 'home
ignition zone'--a home and its surroundings within 100 feet (which
may include neighboring homes)." 

The authors noted that wildfires are driven by climate and climate
change, and criticized the current federal management approach
embodied in the 2022 Wildfire Crisis Strategy, and in the 2021
Infrastructure Act and 2022 Inflation Reduction Act, that is
focused on thinning tens of millions of acres of public, private,
and Tribal forests in the western U.S. The authors concluded that
we must recognize that wildfire in forests and other wildlands is
not only inevitable, but also there is an "ecological necessity"
that wildfires occur for native biodiversity benefits. The
scientists concluded that the "best way" to protect homes and lives
is to focus attention and resources directly on communities, using
proven methods to make them fire safe, noting that the current
approach is leading to more, not fewer, losses of homes and lives.
They promoted "direct funding and technical assistance to
communities", instead of spending many billions of dollars managing
forests distant from homes. 

USFS (U.S. Forest Service) (2022). Gallinas-Las Dispensas
Prescribed Fire Declared Wildfire Review. U.S. Forest Service,
Office of the Chief, Washington, D.C.

Thinning followed by burning caused a massive fire that destroyed
communities. 

Thinning reduced canopy cover, increasing growth of combustible
grasses; associated pile burning caused a huge wildfire, spreading
rapidly through thinned areas, burning many homes. 

Lesmeister, D.B., et al. (co-authored by U.S. Forest Service).
2019. Mixed-severity wildfire and habitat of an old-forest
obligate. Ecosphere10: Article e02696. 

Denser, older forests with high canopy cover had lower fire
severity and "buffer the negative effects of climate change"
regarding wildfires. 

"Thinned forests have more open conditions, which are associated
with higher temperatures, lower relative humidity, higher wind
speeds, and increasing fire intensity. Furthermore, live and dead
fuels in young forest or thinned stands with dense saplings or
shrub understory will be drier, making ignition and high heat more
likely, and the rate of spread higher because of the relative lack
of wind breaks provided by closed canopies with large trees."

Lesmeister, D.B., et al. (co-authored by U.S. Forest Service).
2021. Northern spotted owl nesting forests as fire refugia: a
30-year synthesis of large wildfires. Fire Ecology 17: Article 32.


More open forests with lower biomass had higher fire severity,
because the type of open, lower-biomass forests resulting from
thinning and other logging activities have "hotter, drier, and
windier microclimates, and those conditions decrease dramatically
over relatively short distances into the interior of older forests
with multi-layer canopies and high tree density..." 

Reilly, M.J., et al. (co-authored by U.S. Forest Service). 2022.
Cascadia Burning: The historic, but not historically unprecedented,
2020 wildfires in the Pacific Northwest, USA. Ecosphere 13: e4070.


Weather conditions primarily determined fire severity, and forest
density was not a factor. 

"We found minimal difference in burn severity among stand
structural types related to previous management in the 2020 fires.
Adaptation strategies for similar fires in the future could benefit
by focusing on ignition prevention, fire suppression, and community
preparedness, as opposed to fuel treatments that are unlikely to
mitigate fire severity during extreme weather."

North, M.P., S.L. Stephens, B.M. Collins, J.K. Agee, G. Aplet, J.F.
Franklin, and P.Z. Fule (co-authored by U.S. Forest Service). 2015.
Reform forest fire management. Science 349: 1280-1281. 

"...fire is usually more efficient, cost-effective, and
ecologically beneficial than mechanical treatments."

Lydersen, J. M., M. P. North, and B. M. Collins (co-authored by
U.S. Forest Service). 2014. Severity of an uncharacteristically
large wildfire, the Rim Fire, in forests with relatively restored
frequent fire regimes. Forest Ecology and Management 328:326-334.

In the Rim fire of 2013, the authors found that mature
mixed-conifer and ponderosa pine forests with "a greater small tree
density tend[ed] to burn with lower severity."

Meigs, G.W., et al. (co-authored by U.S. Forest Service). 2020.
Influence of topography and fuels on fire refugia probability under
varying fire weather in forests of the US Pacific Northwest.
Canadian Journal of Forest Research 50: 636-647. 

	Forests with higher pre-fire biomass are more likely to experience
low-severity fire. 

Thompson, J.R., Spies, T.A., Ganio, L.M. (co-authored by U.S.
Forest Service). 2007. Reburn severity in managed and unmanaged
vegetation in a large wildfire. Proceedings of the National Academy
of Sciences of the United States of America 104: 10743-10748. 

"Areas that were salvage-logged and planted after the initial fire
burned more severely than comparable unmanaged areas."

Thompson, J.R., Spies, T.A. (co-authored by U.S. Forest Service).
2009. Vegetation and weather explain variation in crown damage
within a large mixed-severity wildfire. Forest Ecology and
Management 258: 1684-1694.

	Mature forests with higher canopy cover had lower fire severity. 

Thompson, J., and T.A. Spies (co-authored by U.S. Forest Service).
2010. Exploring Patterns of Burn Severity in the Biscuit Fire in
Southwestern Oregon. Fire Science Brief 88: 1-6. 

"Areas that burned with high severity...in a previous wildfire (in
1987, 15 years prior) were more likely to burn with high severity
again in the 2002 Biscuit Fire. Areas that were salvage-logged and
planted following the 1987 fire burned with somewhat higher fire
severity than equivalent areas that had not been logged and
planted." 

Graham, R., et al. (U.S. Forest Service). 2012. Fourmile Canyon
Fire Findings. Gen. Tech. Rep. RMRS-GTR-289. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station. 110 p.

Thinned forests "were burned more severely than neighboring areas
where the fuels were not treated", and 162 homes were destroyed by
the Fourmile Canyon Fire (see Figs. 45 and 46). 

Morris, W.G. (U.S. Forest Service). 1940. Fire weather on clearcut,
partly cut, and virgin timber areas at Westfir, Oregon. Timberman
42: 20-28. 

"This study is concerned with one of these factors - the
fire-weather conditions near ground level - on a single operation
during the first summer following logging. These conditions were
found to be more severe in the clear-cut area than in either the
heavy or light partial cutting areas and more severe in the latter
areas than in virgin timber."

Countryman, C.M. (U.S. Forest Service). 1956. Old-growth conversion
also converts fire climate. Fire Control Notes 17: 15-19. 

Partial cutting (thinning) increases wildfire severity, due to
microclimate impacts, regardless of whether or how the slash debris
is treated. 
"Although the general relations between weather factors, fuel
moisture, and fire behavior are fairly well known, the importance
of these changes following conversion and their combined effect on
fire behavior and control is not generally recognized. The term
'fireclimate,' as used here, designates the environmental
conditions of weather and fuel moisture that affect fire behavior.
It does not consider fuel created by slash because regardless of
what forest managers do with slash, they still have to deal with
the new fireclimate. In fact, the changes in wind, temperature,
humidity, air structure, and fuel moisture may result in greater
changes in fire behavior and size of control job than does the
addition of more fuel in the form of slash." 
"Conversion which opens up the canopy by removal of trees permits
freer air movement and more sunlight to reach the ground. The
increased solar radiation in turn results in higher temperatures,
lower humidity, and lower fuel moisture. The magnitude of these
changes can be illustrated by comparing the fireclimate in the open
with that in a dense stand."
"A mature, closed stand has a fireclimate strikingly different from
that in the open. Here nearly all of the solar radiation is
intercepted by the crowns. Some is reflected back to space and the
rest is converted to heat and distributed in depth through the
crowns. Air within the stand is warmed by contact with the crowns,
and the ground fuels are in turn warmed only by contact with the
air. The temperature of fuels on the ground thus usually
approximates air temperature within the stand." 
"Temperature profiles in a dense, mixed conifer stand illustrate
this process (fig. 2). By 8 o'clock in the morning, air within the
crowns had warmed to 68° F. Air temperature near the ground was
only 50°. By 10 o'clock temperatures within the crowns had reached
82° and, although the heat had penetrated to lower levels, air near
the surface at 77° was still cooler than at any other level. At
2:00 p.m., air temperature within the stand had become virtually
uniform at 87°. In the open less than one-half mile away, however,
the temperature at the surface of pine litter reached 153° at 2:00
p.m." 
"Because of the lower temperature and higher humidity, fuels within
the closed stand are more moist than those in the open under
ordinary weather conditions. Typically, when moisture content is 3
percent in the open, 8 percent can be expected in the stand." 
"Moisture and temperature differences between open and closed
stands have a great effect on both the inception and the behavior
of fire. For example, fine fuel at 8-percent moisture content will
require nearly one-third more heat for ignition than will the same
fuel at 3-percent moisture content. Thus, firebrands that do not
contain enough heat to start a fire in a closed stand may readily
start one in the open."
"When a standard fire weather station in the open indicates a
temperature of 85° F., fuel moisture of 4 percent, and a wind
velocity of 15 m.p.h.--not unusual burning conditions in the
West--a fire starting on a moderate slope will spread 4.5 times as
fast in the open as in a closed stand. The size of the suppression
job, however, increases even more drastically." 
"Greater rate of spread and intensity of burning require control
lines farther from the actual fire, increasing the length of
fireline. Line width also must be increased to contain the hotter
fire. Less production per man and delays in getting additional
crews complicate the control problem on a fast-moving fire. It has
been estimated that the size of the suppression job increases
nearly as the square of the rate of forward spread. Thus, fire in
the open will require 20 times more suppression effort. In other
words, for each man required to control a surface fire in a mature
stand burning under these conditions, 20 men will be required if
the area is clear cut." 
"Methods other than clear cutting, of course, may bring a less
drastic change in fireclimate. Nevertheless, the change resulting
from partial cutting can have important effects on fire. The
moderating effect that a dense stand has on the fireclimate usually
results in slow-burning fires. Ordinarily, in dense timber only a
few days a year have the extreme burning conditions under which
surface fires produce heat rapidly enough to carry the fire into
the crowns. Partial cutting can increase the severity of the
fireclimate enough to materially increase the number of days when
disastrous crown fires can occur." 

SNEP (co-authored by U.S. Forest Service). 1996. Sierra Nevada
Ecosystem Project, Final Report to Congress: Status of the Sierra
Nevada. Vol. I: Assessment summaries and management strategies.
Davis, CA: University of California, Davis, Center for Water and
Wildland Resources. 

"Timber harvest, through its effects on forest structure, local
microclimate, and fuel accumulation, has increased fire severity
more than any other recent human activity." 

Chen, J., et al. (co-authored by U.S. Forest Service). 1999.
Microclimate in forest ecosystem and landscape ecology: Variations
in local climate can be used to monitor and compare the effects of
different management regimes. BioScience 49: 288-297.  

When moving from open forest areas, resulting from logging, and
into dense forests with high canopy cover, "there is generally a
decrease in daytime summer temperatures but an increase in
humidity..." 

The authors reported a 5 C difference in ambient air
temperature between a closed-canopy mature forest and a forest with
partial cutting, like a commercial thinning unit (Fig. 4b), and
noted that such differences are even greater than the increases in
temperature predicted due to anthropogenic climate change. 

Dombeck, M. (U.S. Forest Service Chief). 2001. How Can We Reduce
the Fire Danger in the Interior West. Fire Management Today 61:
5-13.

"Some argue that more commercial timber harvest is needed to remove
small-diameter trees and brush that are fueling our worst wildlands
fires in the interior West. However, small-diameter trees and brush
typically have little or no commercial value. To offset losses from
their removal, a commercial operator would have to remove large,
merchantable trees in the overstory. Overstory removal lets more
light reach the forest floor, promoting vigorous forest
regeneration. Where the overstory has been entirely removed,
regeneration produces thickets of 2,000 to 10,000 small trees per
acre, precisely the small-diameter materials that are causing our
worst fire problems. In fact, many large fires in 2000 burned in
previously logged areas laced with roads. It seems unlikely that
commercial timber harvest can solve our forest health problems."

Hanson, C.T. 2021. Is "Fuel Reduction" Justified as Fire Management
in Spotted Owl Habitat? Birds 2: 395-403. 

	Thinning followed by burning and post-fire logged areas had higher
overall fire severity.  

"Within the forest types inhabited by California Spotted Owls,
high-severity fire occurrence was not higher overall in unmanaged
forests and was not associated with the density of pre-fire snags
from recent drought in the Creek Fire, contrary to expectations
under the fuel reduction hypothesis. Moreover, fuel-reduction
logging in California Spotted Owl habitats was associated with
higher fire severity in most cases. The highest levels of
high-severity fire were in the categories with commercial logging
(post-fire logging, private commercial timberlands, and commercial
thinning), while the three categories with lower levels of
high-severity fire were in forests with no recent forest management
or wildfire, less intensive noncommercial management, and unmanaged
forests with re-burning of mixed-severity wildfire, respectively."


Baker, B.C., and C.T. Hanson. 2022. Cumulative tree mortality from
commercial thinning and a large wildfire in the Sierra Nevada,
California. Land 11: Article 995.

	Thinning followed by burning increases overall fire severity. 

"Similar to the findings of Hanson (2022) in the Antelope Fire of
2021 in northern California, in our investigation of the Caldor
Fire of 2021 we found significantly higher cumulative severity in
forests with commercial thinning than in unthinned forests,
indicating that commercial thinning killed significantly more trees
than it prevented from being killed in the Caldor Fire...Despite
controversy regarding thinning, there is a body of scientific
literature that suggests commercial thinning should be scaled up
across western US forest landscapes as a wildfire management
strategy. This raises an important question: what accounts for the
discrepancy on this issue in the scientific literature? We believe
several factors are likely to largely explain this discrepancy.
First and foremost, because most previous research has not
accounted for tree mortality from thinning itself, prior to the
wildfire-related mortality, such research has underreported tree
mortality in commercial thinning areas relative to unthinned
forests. Second, some prior studies have not controlled for
vegetation type, which can lead to a mismatch when comparing
severity in thinned areas to the rest of the fire area given that
thinning necessarily occurs in conifer forests but unthinned areas
can include large expanses of non-conifer vegetation types that
burn almost exclusively at high severity, such as grasslands and
chaparral. Third, some research reporting effectiveness of
commercial thinning in terms of reducing fire severity has been
based on the subjective location of comparison sample points
between thinned and adjacent unthinned forests. Fourth, reported
results have often been based on theoretical models, which
subsequent research has found to overestimate the effectiveness of
thinning. Last, several case studies draw conclusions about the
effectiveness of thinning as a wildfire management strategy when
the results of those studies do not support such a conclusion, as
reviewed in DellaSala et al. (2022)." (internal citations omitted)

DellaSala, D.A., B.C. Baker, C.T. Hanson, L. Ruediger, and W.L.
Baker. 2022. Have western USA fire suppression and megafire active
management approaches become a contemporary Sisyphus? Biological
Conservation 268: Article 109499. 

	Thinning followed by burning increases overall fire severity. 

With regard to a previous U.S. Forest Service study claiming that
commercial thinning effectively reduced fire severity in the large
Wallow fire of 2011 in Arizona, DellaSala et al. (2022, Section
5.1) conducted a detailed accuracy check and found that the
previous analysis had dramatically underreported high-severity fire
in commercial thinning units, and forests with commercial thinning
in fact had higher fire severity, overall. 

DellaSala et al. (2022, Section 5.2) also reviewed several U.S.
Forest Service studies relied upon by Prichard et al. (2021) for
the claim that commercial thinning is an effective fire management
approach and found that the actual results of these cited studies
did not support that conclusion. 

Beschta, R.L.; Frissell, C.A.; Gresswell, R.; Hauer, R.; Karr,
J.R.; Minshall, G.W.; Perry, D.A.; Rhodes, J.J. 1995. Wildfire and
salvage logging. Eugene, OR: Pacific Rivers Council.

"We also need to accept that in many drier forest types throughout
the region, forest management may have set the stage for fires
larger and more intense than have occurred in at least the last few
hundred years."
"With respect to the need for management treatments after fires,
there is generally no need for urgency, nor is there a universal,
ecologically-based need to act at all. By acting quickly, we run
the risk of creating new problems before we solve the old ones." 
"[S]ome argue that salvage logging is needed because of the
perceived increased likelihood that an area may reburn. It is the
fine fuels that carry fire, not the large dead woody material. We
are aware of no evidence supporting the contention that leaving
large dead woody material significantly increases the probability
of reburn."

Morrison, P.H. and K.J. Harma. 2002. Analysis of Land Ownership and
Prior Land Management Activities Within the Rodeo & Chediski Fires,
Arizona. Pacific Biodiversity Institute, Winthrop, WA. 13 pp.

	Previous logging was associated with higher fire severity. 

Donato DC, Fontaine JB, Campbell JL, Robinson WD, Kauffman JB, Law
BE. 2006. Science 311: 352. 

"In terms of short-term fire risk, a reburn in [postfire] logged
stands would likely exhibit elevated rates of fire spread, fireline
intensity, and soil heating impacts...Postfire logging alone was
notably incongruent with fuel reduction goals." 

Hanson, C.T., Odion, D.C. 2006. Fire Severity in mechanically
thinned versus unthinned forests of the Sierra Nevada, California.
In: Proceedings of the 3rd International Fire Ecology and
Management Congress, November 13-17, 2006, San Diego, CA. 

"In all seven sites, combined mortality [thinning and fire] was
higher in thinned than in unthinned units. In six of seven sites,
fire-induced mortality was higher in thinned than in unthinned
units...Mechanical thinning increased fire severity on the sites
currently available for study on national forests of the Sierra
Nevada."

Platt, R.V., et al. 2006. Are wildfire mitigation and restoration
of historic forest structure compatible? A spatial modeling
assessment. Annals of the Assoc. Amer. Geographers 96: 455-470.

"Compared with the original conditions, a closed canopy would
result in a 10 percent reduction in the area of high or extreme
fireline intensity. In contrast, an open canopy [from thinning] has
the opposite effect, increasing the area exposed to high or extreme
fireline intensity by 36 percent. Though it may appear
counterintuitive, when all else is equal open canopies lead to
reduced fuel moisture and increased midflame windspeed, which
increase potential fireline intensity."

Cruz, M.G, and M.E. Alexander. 2010. Assessing crown fire potential
in coniferous forests of western North America: A critique of
current approaches and recent simulation studies. Int. J. Wildl.
Fire. 19: 377-398. 

The fire models used by the U.S. Forest Service falsely predict
effective reduction in crown fire potential from thinning: 
"Simulation studies that use certain fire modelling systems (i.e.
NEXUS, FlamMap, FARSITE, FFE-FVS (Fire and Fuels Extension to the
Forest Vegetation Simulator), Fuel Management Analyst (FMAPlus),
BehavePlus) based on separate implementations or direct integration
of Rothermel's surface and crown rate of fire spread models with
Van Wagner's crown fire transition and propagation models are shown
to have a significant underprediction bias when used in assessing
potential crown fire behaviour in conifer forests of western North
America. The principal sources of this underprediction bias are
shown to include: (i) incompatible model linkages; (ii) use of
surface and crown fire rate of spread models that have an inherent
underprediction bias; and (iii) reduction in crown fire rate of
spread based on the use of unsubstantiated crown fraction burned
functions. The use of uncalibrated custom fuel models to represent
surface fuelbeds is a fourth potential source of bias." 

DellaSala et al. (2013) (letter from over 200 scientists):

"Numerous studies also document the cumulative impacts of post-fire
logging on natural ecosystems, including...accumulation of logging
slash that can add to future fire risks..."

DellaSala et al. (2015) (letter from over 200 scientists): 

"Post-fire logging has been shown to eliminate habitat for many
bird species that depend on snags, compact soils, remove biological
legacies (snags and downed logs) that are essential in supporting
new forest growth, and spread invasive species that outcompete
native vegetation and, in some cases, increase the flammability of
the new forest. While it is often claimed that such logging is
needed to restore conifer growth and lower fuel hazards after a
fire, many studies have shown that logging tractors often kill most
conifer seedlings and other important re-establishing vegetation
and actually increases flammable logging slash left on site.
Increased chronic sedimentation to streams due to the extensive
road network and runoff from logging on steep slopes degrades
aquatic organisms and water quality." 

Bradley, C.M. C.T. Hanson, and D.A. DellaSala. 2016. Does increased
forest protection correspond to higher fire severity in
frequent-fire forests of the western USA? Ecosphere 7: article
e01492.  

In the largest study on this subject ever conducted in western
North American, the authors found that the more trees that are
removed from forests through logging, the higher the fire severity
overall: 
"We investigated the relationship between protected status and fire
severity using the Random Forests algorithm applied to 1500 fires
affecting 9.5 million hectares between 1984 and 2014 in pine (Pinus
ponderosa, Pinus jeffreyi) and mixed-conifer forests of western
United States, accounting for key topographic and climate
variables. We found forests with higher levels of protection [from
logging] had lower severity values even though they are generally
identified as having the highest overall levels of biomass and fuel
loading."

Dunn, C.J., et al. 2020. How does tree regeneration respond to
mixed-severity fire in the western Oregon Cascades, USA? Ecosphere
11: Article e03003. 
	
	Forests that burned at high-severity had lower, not higher,
overall pre-fire tree densities. 	
 
Moomaw et al. (2020) (letter from over 200 scientists:
https://johnmuirproject.org/2020/05/breaking-news-over-200-top-u-s-climate-and-forest-scientists-urge-congress-protect-forests-to-mitigate-climate-crisis/):

"Troublingly, to make thinning operations economically attractive
to logging companies, commercial logging of larger, more
fire-resistant trees often occurs across large areas. Importantly,
mechanical thinning results in a substantial net loss of forest
carbon storage, and a net increase in carbon emissions that can
substantially exceed those of wildfire emissions (Hudiburg et al.
2013, Campbell et al. 2012). Reduced forest protections and
increased logging tend to make wildland fires burn more intensely
(Bradley et al. 2016). This can also occur with commercial
thinning, where mature trees are removed (Cruz et al. 2008, Cruz et
al. 2014). As an example, logging in U.S. forests emits 10 times
more carbon than fire and native insects combined (Harris et al.
2016). And, unlike logging, fire cycles nutrients and helps
increase new forest growth."

Moomaw et al. (2021) (letter from over 200 scientists:
https://bit.ly/3BFtIAg):

"[C]ommercial logging conducted under the guise of "thinning" and
"fuel reduction" typically removes mature, fire-resistant trees
that are needed for forest resilience. We have watched as one large
wildfire after another has swept through tens of thousands of acres
where commercial thinning had previously occurred due to extreme
fire weather driven by climate change. Removing trees can alter a
forest's microclimate, and can often increase fire intensity. In
contrast, forests protected from logging, and those with high
carbon biomass and carbon storage, more often burn at equal or
lower intensities when fires do occur.

Bartowitz, K.J., et al. 2022. Forest Carbon Emission Sources Are
Not Equal: Putting Fire, Harvest, and Fossil Fuel Emissions in
Context. Front. For. Glob. Change 5: Article 867112. 

The authors found that logging conducted as commercial thinning,
which involves removal of some mature trees, substantially
increases carbon emissions relative to wildfire alone, and
commercial thinning "causes a higher rate of tree mortality than
wildfire."

Evers, C., et al. 2022. Extreme Winds Alter Influence of Fuels and
Topography on Megafire Burn Severity in Seasonal Temperate
Rainforests under Record Fuel Aridity. Fire 5: Article 41. 

The authors found that dense, mature/old forests with high biomass
and canopy cover tended to have lower fire severity, while more
open forests with lower canopy cover and less biomass burned more
severely. 

Baker, W.L., C.T. Hanson, M.A. Williams, and D.A. DellaSala. 2023.
Countering Omitted Evidence of Variable Historical Forests and Fire
Regime in Western USA Dry Forests: The Low-Severity-Fire Model
Rejected. Fire 6: Article 146. 

A pattern of omissions of peer-reviewed, published reply articles,
which refuted and discredited U.S. Forest Service response
articles, created a "falsification" of the scientific record
regarding historical forest density and fire regimes. The corrected
record shows that historical forests were much denser on average
than assumed by the Forest Service and were shaped by
mixed-severity fire, not merely low-severity fire.

Sincerely, 
 
Chad Hanson, Ph.D., Ecologist			 
John Muir Project			 
P.O. Box 897		
Ridgecrest, CA  93556				
530-273-9290
cthanson1@gmail.com