Bill introduced to promote prescribed fire intends to reduce fire risk
wildfiretoday.com
wildfiretoday.com
Don't we generally know that we need to do more prescribed fire burning? Isn't this generally highjacked by the timber industry to protect valuable "product?"
If that's true, will this federal bill address that? It seems like it allocates money but doesn't talk about the other 53% of the lands that are not federally managed. And, it doesn't talk about whether the 47% lands are the problem or not. In Oregon where I live, the massive fires were ten miles from me in largely residentially adjacent lands. Are those going to be helped?
I love that this bill offers jobs to formerly incarcerated people that have been fighting fires.
If I'm wrong about my first assumption, would really like to know.
Also, I saw a statistic that said California needs to do prescribed burns of about a million acres a year to manage wildfire risk. They are currently doing only 40,000. But these massive fires over the last month are approaching that million acre number: does anyone know if next year we will be safer because of those fires?
1) the lumber industry obviously prefers clearcutting in the short-term, but generally follows selection laws if they get access to more forests and the logging equipment fits, but that means logging roads.
2) It's needed to harvest fallen trees within about a year of a fall for lumber. By 6 years they're rotten and not economically viable, but still contribute to fires - this was a problem in 2020.
3) Generally scheduled, controlled burns only quickly burn the forest floor (detritis like branches, deadfalls, etc.) and some outside bark, which trees evolved to tolerate, and not the inner core of trees, so doesn't affect logging.
When you wait too long, trees actually heat and explode, setting the canopy on fire far and wide. If you make charcoal, that's a more persistent fire.
Source: very lucky to have grown up outside a national park, which makes one a hard-core ecologist.
If we manage the forest as a company and monoculture of trees, then fallen trees are money and must be harvested for profit. If we manage the forest as an ecosystem, fallen trees create entire sub-ecosystems and provide necessary refuges for amphibians, mammals, birds and invertebrates. They belong to the forest, boost biodiversity, and shouldn't removed necessarily. Not unless they block a road or lie in a problematic area. Not by default.
It's worth noting that whenever you see big clearcuts, its almost always private land (aka, "tree farms"). That is where most of the wood comes from these days. I'm really not sure about the regulations on those lands, considering they can pose a hazard for neighboring areas if improperly managed.
The total amount of burned area in California is very small compared to the area that is susceptible to severe fires, so unfortunately this year didn't move the needle much. Worse, really hot fires kill everything, and actually make it easier for dense brush and stunted trees to pop up again.
What you really want in drier areas is an open forest with few, large trees.
This is what the aborigines in Australia used to do:
'To Help Australia, Look to Aboriginal Fire Management'
https://www.yesmagazine.org/environment/2020/01/13/australia...
A few things that have stuck with me over the years of discussing his work:
* Much like floods, he returns the same burn areas year after year (ex. Paradise, CA and surrounding area). Some of that is recent encroachment into wilderness boundary areas, but much is also historically-inhabited land whose climate has changed drastically.
* Prescribed burns quickly run up against environmental regulations (esp. those intended to reduce smog), property rights concerns, and coordinating the patchwork of agencies and individuals who own and manage this land - BLM, USFS, CalFire, Sierra Pacific Industries, &c.
* To hear him tell it, CalFire is woefully incompetent and fiscally irresponsible, leaving much of the work to over-burdened and under-funded federal agencies. I live in a CalFire "State Responsibility Area" (i.e. any fire in my area would be served by CalFire), and I've seen very little actual evidence to contradict him.
Yes, everyone generally agrees we need to do more prescribed burns, but it's easier said than done. The three main impediments (at least in CA) seem to be: [0]
1. tight environmental regulations
2. limited resources
3. concerns about negative public opinion.
I think the biggest problem is there is a patchwork of air quality regulations in CA plus federal regulations like the Clean Air Act which makes it very difficult to do prescribed burns.[1] So this bill might help with the federal regulations but I'm not sure how it would impact local regs.
[0] https://www.sfgate.com/bayarea/article/Top-scientist-knew-Bi...
[1] https://reason.com/2020/09/14/western-wildfires-can-be-preve...
For example is known that narcos expecting to land a cargo of drugs typically start wildfires at several Km of the landing point. They use that to trick the police to concentrate in the opposite extreme of the map.
Yes.
"Isn't this generally highjacked by the timber industry to protect valuable "product?""
No, I don't believe that to be the case. Broadly speaking, prescribed burns are thwarted by a mix of local objections to smoke, noise and traffic ... and environmental objections relating to specific watersheds, protected species and (literally) individual birds that are witnessed in the burn area.[1] Remember: this is California - these people didn't move here to not have their very, very specific voice, and preferences, heard and respected. (I kid because I love)
"But these massive fires over the last month are approaching that million acre number: does anyone know if next year we will be safer because of those fires?"
I can't speak to "safer" but, absolutely there will be less fuel to burn next year. Almost the entire land area of Napa County has burned this year. I suspect they can skate for many decades on this (rapid, violent) fuels reduction.
Personally, as the owner of 25-ish acres of wooded land in this area (Marin County), I am not waiting. We are simulating fire by dramatically reducing fuel loads on our lands. I am assuming these forests will burn and trying to reduce the speed and intensity of that eventual fire.
[1] https://www.newyorker.com/magazine/2019/08/26/a-trailblazing...
As a lifelong sonoma county resident, curious why were you not managing fuels already? It's a duty to your neighbors. CalFire is very aggressive up here in certain areas, and will red tag your property if it gets past a point.
> "No, I don't believe that to be the case. Broadly speaking, prescribed burns are thwarted by a mix of local objections to smoke, noise and traffic"
Can confirm this for Sonoma County, CA. They used to burn a lot when I was young. Not much anymore, mostly because of the $$$ moving up here and they have no understanding of the need for it. Well, this is the alternative.
Also, a lot of land is private.
And much of the later "environmental objections" are hijacked by the former Nimby forces, while the right wing uses this phony environmentalism to point the rural folks at the left instead of real estate and development interests that drive all this.
This is where they lose me. The reason why wildfires exist in the first place is because of climate change; deforestation is the opposite of fighting climate change. Very strange California taking a cue out of Trump's climate change denying book.
Yes and no. One of the features of climate change is that some wet areas become deserts while some currently-dry areas become wet. Planting trees in an area becoming desert (like California) will only encourage the inevitable disastrous burn.
Planting trees in an area becoming wetter would do a great deal of good. Those trees are likely to survive to scrub CO2.
Jack Cohen is a retired U.S. Forest Service Research fire scientist who has spent years determining how structures ignite during extreme wildfires. In a September 21, 2020 article he wrote for Wildfire Today with Dave Strohmaier, they addressed how homes ignite during extreme wildfires.
“Surprisingly, research has shown that home ignitions during extreme wildfires result from conditions local to a home. A home’s ignition vulnerabilities in relation to nearby burning materials within 100 feet principally determine home ignitions. This area of a home and its immediate surroundings is called the home ignition zone (HIZ). Typically, lofted burning embers initiate ignitions within the HIZ – to homes directly and nearby flammables leading to homes. Although an intense wildfire can loft firebrands more than one-half mile to start fires, the minuscule local conditions where the burning embers land and accumulate determine ignitions. Importantly, most home destruction during extreme wildfires occurs hours after the wildfire has ceased intense burning near the community; the residential fuels – homes, other structures, and vegetation – continue fire spread within the community.
“Uncontrollable extreme wildfires are inevitable, however, by reducing home ignition potential within the HIZ we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem.”
An interesting counterpoint is to look at a managed forest in the northwest to get a feel for what companies that harvest wood do to manage fire risk.
Of course that was one of FDR's most successful programs, and one which I feel could be applied here as well. The country needs both tradespeople and infrastructure maintenance in a big way and doing that by funding large engineering firms is extremely inefficient.
For some people just getting the experience of going to a job (as well as a resume line) would really help them, and... we need some stuff done for sure in the US.
There was humid areas with lakes and lots of animals in what is now the Prehistoric Sahara, burnt for pastures until desert
There was lots of extinct species in what is now Australia, and it was more humid in the past. Arid, subdesert, desert again.
Brazil has a huge stupidity problem, some new deserts ordered and in the way
Indonesia idem,
Russia has extensive wildfires in 2019, happily running towards the same path
We don't even understand well the dynamics and ecology of soil, and all that we can parrot again and again is lets burn more, lets burn more, that will solve it all... we are not burning enough fast.
We know that fallen trees are essential for many species of invertebrates and vertebrates, Not allowed anymore it seems. We must clean the area and turn nature into a cartoon.
Being an arsonist is not only the perfect crime, it seems that is even the fastest way to became a local hero. We are even justifying and giving reasons to them
No it’s not.
2) Forest fires have been controlled and contained for the last ~100 years on the west coast of America.
3) Forests are not being burned at anywhere close to the rate that they would naturally.
4) Fire is not the process by which these places became arid.
The problem is that we can't survive just with this technique anymore, because we desperately need more forests in a "safety level of rainforest" or close to it, to have any chance to heal the climate. Unless we create a CO2 extracting machine, trees, plants and algae are still our best bet.
This rhetoric of "lets manage ecosystems as they did in the roman empire", maybe could work 200 years ago but now we are in a different situation.
4) Places became arid in part because there is not topsoil anymore, so nobody can grow here enough fast, so there is not water storing creatures anymore. This happens often by past fires followed by rains that first mineralize the soil, then turn it into dust and then wash it down the streams in a mud flood.
Removing mechanically the dry weeds, would have the same effects but without the counterparts.
(...talking about lack of understanding, here comes the tunnel vision)
Hem, not. Obviously. Is several levels more complex than that. You forgot at least two really big factors here.
Any loss of plant life due to a forest fire is quickly replaced as new growth is able to take advantage of new light/water/nutrient resources.
But, it was a massive uncontrolled fire. A lower temperature controlled burn may (probably?) not have caused that. Also if it had not occurred on such steep slopes maybe erosion wouldn't have been such a problem.
And what of those ecosystems down stream that would have benefited from the influx in nutrients?
The erosion was quite heavy though as the fires were followed by very heavy (and unusual) torrential rains. You could see the deep channels in the slopes and the roads were also covered with sediment. They had to bring in heavy machinery for that as well.
The area is recovering nicely now, it's grass with small saplings and I was up there this year and didn't really see any new erosion at all.
But I remember reading (somewhere) part of the reason Australia became arid is repeated mass burning by Aboriginal people. Anyone know how true that really is (or is not)?
Misguided, fact-free views like yours cost lives and damage the planet.
"In February 2020, Nature Sustainability published this terrifying conclusion: California would need to burn 20 million acres — an area about the size of Maine — to restabilize in terms of fire."
Naïve calculation thus puts the cost at 2 billion dollars, or about 1/3rd of the final cost of the east span of the Bay Bridge. :)
And more than $1.6B has been spent on fire suppression in California this year alone: https://en.wikipedia.org/wiki/2020_California_wildfires#cite...
So when you think about the alternatives, $2B to clear California's fire debt sounds pretty reasonable.
At least in some cases, the main restriction is environmental protections laws and liability concerns. You want to start a controlled burn? What's the risk? What species live in the area? Are any endangered? Are you sure? Will anyone be hurt during this blaze? Have you filed the environmental impact statement, risk mitigation plan, incident management documents, and obtained approval from all relevant agencies? How much smoke will it generate? What's going to be IN the smoke? What do you mean you don't know the exact contents of the smoke; how can you get a permit for emitting smoke without knowing what in it? Etc.
In California in particular, controlled burns need approval from the local Air District, and they have to give approval on the day. It's not unheard of for a planned, approved burn to be shut down at the last minute because the day is a bit too smoggy already. There's always someone willing to pop up and argue against the controlled burn; local residents worried about safety, or even the American Lung Association worried about smoke inhalation. Also, the people in charge of starting burns can be held liable if they go wrong, but will not be held liable if they opt not to start a burn, and then disaster ensues.
It's possible the timber industry is somewhere behind that, but we seem quite capable of hamstringing ourselves "honestly" too, so I'm not sure.
In any case, yes. California burns around 20k acres per year, but needs to be burning more like 1m acres per year, AND needs to burn a 20m acre backlog. Everyone is in agreement that this needs to happen, but (just like so many other Californian problems) there's no obvious path forward. The system is setup at every level to stop this, and it has enormous inertia. Experts hope than in a few years, they might be able to get up to as high as 40k acres per year...which won't even be a noticeable improvement. There's no single villain causing an otherwise functioning system to fail; the system is the problem.
I found this article quite interesting: https://massivesci.com/articles/megafire-california-climate-...
If populated areas are nearby, logging and subsequent mowing flat are alternatives in some circumstances (and act as a great carbon sink).
1. Source: I worked and volunteered many years in college on the Kanza Tallgrass Prairie preserve which experienced natural fires regularly through it's evolutionary history.
Less chances of somebody setting the forest on fire unintentionally, and vice versa.
You also need prescribed forest clearings inside the forest around settlements to create multiple rings of fire stops.
Absolutely. I've got somewhere an edition of Tacitus' Germania with commentary that states as a matter of fact, no explanation needed that "the forest is not part of the human sphere". Why is this so controversial that it needs to be downvoted?
It is baffling that anyone would want to live on the wrong side of the urban-wilderness interface, especially if wilderness means wildfire risk.
My house in a Michigan forest has a very, very different risk profile from a home in a California forest. And California is a big state, I'm sure there are forests that have similarly low risk profiles.
Well, there used to be. For example the coastal quasi-rainforest in Big Basin near Santa Cruz.
But climate change appears to have pushed places like that into the burn zone. Nowadays even Olympic National Park, an area full of temperate rainforest, is experiencing wildfire.
it seems like pretty much any forest area of California is at wildfire risk these days.
People have been shown to be willing to rebuild repeatedly in fire zones, with massive economic and public safety impact. Makes sense to legislate to prevent this.
Some do, some don't. California isn't the whole world.
Edit:
> Wildfires are among the most common forms of natural disaster in some regions, including Siberia, California, and Australia.[17][18][19] Areas with Mediterranean climates or in the taiga biome are particularly susceptible.
California and Australia are outliers. Writing off forests in general just because particular sorts of forests are prone to burning doesn't make sense.
It's funny. In a recent discussion I was arguing against someone wanting to increase power costs on rural customers, because I think doing so carelessly would impact the food supply chain. But it doesn't take too much "living in forests is great" foolish selfishness in the middle of a discussion of wildfires to make me wonder if I was on the wrong side of that one.
I've lived in the forest for the last ten years. Nothing better. Sure there's risks; there's risks everywhere.
I agree but this sort of jumps to heart of things. What do you do with the many, many houses already there? Not just houses but people, people with considerable political influence, along with the industries that build this sort of house and everything depending on that? I mean, this is so thorny a problem that I expect nothing with come of the sensible solution and we're just going to have "fires as far as the eye can see" here in California.
Either clear the forest, or demolish them.
Fire breaks are really effective for small fires in moderate weather conditions. The kind of fires we saw in Oz or Cali jump straight over them. Look at these maps from late last year from the guardian[0]. The fires were jumping 20kms or more at a stretch. If look down to the snowy mountains map, you can see where a strong change in wind sent ember attacks to every ridge line over successive days. Unless your fire break clears every ridge you can't stop these kind of fires.
Also, since all the misinformation last year in Australia in the msm about lack of back burning and arson being the major causes of fires. I can't speak to the experience in calu, but we have now found that back burning had actually increased 10 fold before the fires from the previous 10 year period, but suitable conditions for back burning had also decreased by more than a third. Lightning strikes were responsible for most bushfires, with only about 1-3% being deliberately lit. Hell, in the midst of the firestorms, the sudden updraft of smoke and ash into the atmosphere was creating it's own mini weather events including more lightning.
[0] https://www.theguardian.com/news/datablog/2019/nov/21/how-au...
I think having them than not having them is still better than nothing
“In Oregon, a similar story is unfolding—except there, wildfire emissions have managed to surpass annual transportation emissions as well.”
https://qz.com/1903191/western-wildfires-are-producing-a-rec...
This was weeks ago before the recent fires in Napa, Zogg, and the August complex kept burning.
Kinda incredible and gives you perspective into how much co2 is being released.
So if a wooded area burns and then grows back again it is carbon-neutral.
We could spend money to eke out a little around the margins like using more paid firefighters to do mid week burns. It’s not addressing the main issue, though. The climate is changing.
Senate bill would promote controlled burns to reduce wildfire risk
Let's not subsidize the exurbs, but get people away from dry Forests.
Short of resolving the NIMBY problem that prevents higher-density construction in fire-safe areas, paying residents in fire-prone areas to harden their communities is the best choice out of a selection of bad options.
Also keep in mind that keeping people away from fires does nothing to reduce the smoke problem, which is very severe in its own right. The solution needs to be fewer fires, whether they pose an immediate risk to human life or not.
No, the NIMBY problem must be faced head-on. No more avoidance.
My opinion is that this legislation does not go far enough to address the chronic disregard of action to inhibit these cataclysmic events. I would much rather have the government over-correct and over-allocate instead of taking an incremental approach on this. I do not want to wake up to months of awful quality air or see the forests that I have come to love so much be scorched more than is necessary.
Jack Cohen is a retired U.S. Forest Service Research fire scientist who has spent years determining how structures ignite during extreme wildfires. In a September 21, 2020 article he wrote for Wildfire Today with Dave Strohmaier, they addressed how homes ignite during extreme wildfires.
“Surprisingly, research has shown that home ignitions during extreme wildfires result from conditions local to a home. A home’s ignition vulnerabilities in relation to nearby burning materials within 100 feet principally determine home ignitions. This area of a home and its immediate surroundings is called the home ignition zone (HIZ). Typically, lofted burning embers initiate ignitions within the HIZ – to homes directly and nearby flammables leading to homes. Although an intense wildfire can loft firebrands more than one-half mile to start fires, the minuscule local conditions where the burning embers land and accumulate determine ignitions. Importantly, most home destruction during extreme wildfires occurs hours after the wildfire has ceased intense burning near the community; the residential fuels – homes, other structures, and vegetation – continue fire spread within the community.
“Uncontrollable extreme wildfires are inevitable, however, by reducing home ignition potential within the HIZ we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem.”
[0]: for instance, https://www.pri.org/stories/2020-09-01/california-and-austra...
* 33 million acres of forest in CA, 57% owned by the feds, 3% by CA, 14% by the logging industry, 26% by others
* $200/acre for prescribed burns, $1000/acre for thinning, ~$800/acre on average for the US fire service
* 1.1 million acres need treatment each year (~$1B/year) to be effective, according to the little hoover commission
* ~$2B committed by CA, but over at least 5 years
* this bill would appropriate $300M/yr from feds
on the flipside, it's harder to pin down benefits. they cite $9B in costs from one fire, but how much of that is (socialized) losses from excessive (private) risk-taking? it's unclear, but likely not none. how does insurance account for and/or distort that risk?
none of the articles spend much time quantifying health or environmental costs (e.g., CO₂e) of forest fires on the population, and the potential reductions from better management.
it's hard to take a reasonable position without knowing the magnitude of these benefits as well.
https://www.msn.com/en-us/weather/topstories/20000-evacuees-...
https://www.sfchronicle.com/california-wildfires/article/Hid...
Attaching costs to these is difficult.
A chronically homeless person costs the tax payer an average of $35,578 per year.
https://endhomelessness.org/resource/ending-chronic-homeless...
Probably high-side, but a portion of the fire-displaced are likely to become so. If we assume half that cost, displacement alone is ~$340 million/yr.
The US puts a statistical quality year of life at $129,000. Life expectancy aged 65 is 20 years. Again, reducing this by half (assuming premature deaths are spread across the age cohort), we get a ~$4 billion value. This would again be an annually-incurred cost.
it's similar to the discussion around flood maps in relation to assessors/appraisers, risk adjusters, fema, and insurance. those maps are at least in part designed to apportion risk and responsibility.
Urban-wilderness interfaces are major feaatures of the San Francisco Bay Area, Los Angeles, Ventura, Santa Barbara, San Diego, Vacaville, and other counties and metro areas.
The prospects for major urban-impinging wildfires in Solono, Alameda, Contra Costa, Santa Clara, San Mateo, Marin, Sonoma, and Napa counties, even if generally subject to less-severe conditions (lower temps and winds, higher humidities) is high and growing. (Several of these regions have seen major fires.)
Structural damage and economic would be extreme.
The problem is, the more money you make available, the more that the agencies will find to justify that it needs to be spent. How? Well, we'll figure that out later. Probably something having to do with more planes, technology, contractors, etc. I.e. bandaids.
Seems similar to healthcare -- you pay for treatments, and that's what you're gonna incentivize. As many treatments as doctors can justify, with outcome or root cause only as an afterthought.
The crux of the matter here is that getting forested areas to the point of being able to do controlled/prescribed burns is going to take an insane amount of effort and is only happening to a fraction of the forest needed to keep things under control.
You can't just go start a fire in a forest and hope it goes well. You have to manually go through and clear the brush in the understory, or else the fire will be so hot it will burn down large trees.
Once you've cleared much of the small woody brush, etc that causes these fires to be absolutely massive, regular fires will typically be much more mild and continue helping keep the forest understory clear without requiring much manual labor.
It really is pretty effective, but it does require lots of little fires quite frequently.
Most of it doesn't burn every year, but many places that have been logged and now have no trees will have issues with invasive species that grow quickly and explode into flame.
Those invasive species will be displaced when larger tress grow over them, but in the meantime will be a substantial fire risk.
Having both the invasive species and high fuel loads under large trees leads to megafires.
At the end of the day things are going to burn. The question is can we build better to lessen some parts of the human impact, such as houses not burning to the ground. We may not be able to do anything about the air quality at all.
What grows well after a fire might be different trees that thrive in the current climate. Many parts of Colorado have had fires in pine forests. What grows back will be pinion and scrub.
[0] http://archive.oah.org/special-issues/teaching/2009_12/artic...
[1] https://depts.washington.edu/moving1/map_black_migration.sht...
Once cleared, it’s easy to cut trees down to keep it clear when these trees are smaller.
Same thing with maintaining MANY fire-lines (wide cleared path) crisscrossing their precious forest.
Modern folks expects modern firefighters. And one of the modern tools for today’s firefighter MUST be clear-burning and control-burns.
But do modern folks know this? Noooo, it’s just a pearl-clutching, collective-gasp that their poorly-trained notion expect firefighters not to start fires and ONLY to stop fires.
Me think firefighting unit and forestry management needs to be a bit more cohesive either in principle or practice.
https://lhc.ca.gov/report/fire-mountain-rethinking-forest-ma...
It'll take you through a better-than-surface understanding of the problem history and how we got here, contributing factors, potential solutions, and political/social obstacles.
Doesn't mean we shouldn't still use prescribed burns; we should. Just smaller burns with proper protection to ensure the fire is under control.
“The truth will set you free.” (John 8:32)
The talk that fires are a natural part of a forest and that we should also do prescribed burns seems at odds.
You could argue this is a “flattening the curve” approach to wildfires.
https://www.ted.com/talks/paul_hessburg_why_wildfires_have_g...
So - we're not talking about Old Growth Forest, these are managed forests, humans are already messing with them, the only question is what management strategies to use. "Let's just not manage the forest" is not an option unless you are going to evacuate essentially all the humans from the region. Like, if the only human for 100km is a government official surveying the forest or something, that doesn't need managing. If there's a town there, you have no choice, you're managing that forest now, like it or not.
With this said, if the prescribed burn goes out of control, when they tend to be burnt in the best of conditions.
What's going to happen when a spark hits the ground in the same area when the wind is blowing 35+ knots?
It's time to rethink the WUI.
1.) Everyone in California got rid of their gas vehicle in July and drove an electric vehicle. Fires still burned in August-October.
2.) No change, gas drivers kept their vehicles and no fires happened.
The emissions in California would have been the _same_.
If it were Oregon option 1.) would have been _worse_ than option 2.)
That’s how much co2 is being emitted from these fires. Of course we want to do calculated controlled burns to not let them explode uncontrollably.
https://qz.com/1903191/western-wildfires-are-producing-a-rec...
My question was: are they enough to stop the huge emissions from forest fires, or are we as a species already over that point, and even with the best available methods air quality will get worse every year?
I'm asking because I have vasomotor rhinitis and I'm extremely scared that I won't have any place on earth to hide from air pollution.
Let'ssstarts with pollution, smoke and particals. There will always be emissions from fires. Smaller fires spread the emissions out over several years, while this large fire is many years at once. However smaller fires don't burn as much of their emissions, so the total over a large number of years is greater. However the earth is better able to absorb them when spread out over time. If you live next to the fire it is better to evacuate every 20 years than live next to the smaller fire every year (Small means you don't need to evacuate) for the rest of the world though the small fire means the pollution doesn't reach you and so smaller is better.
If you are worried about CO2, then smaller fire leave a bit more unburned charcoal (sequestered carbon) behind every year and contribute to a long term global cooling. (it will take thousands of years to make up for one year of the rest of what we do, so don't get excited).
According to one article [1] there were 6 deaths from prescribed burns between 1963 and 2013 (and 201 deaths from undesired wildfires). While looking this up,I was also surprised to learn that the #1 cause of death when fighting wildfires is vehicle accidents, and the majority of those are plane crashes