From SMU (Southern Methodist University) comes this press release which really isn’t surprising. North America didn’t have a forest fire suppression program for the last 1400 years, so there wasn’t a fuel buildup issue like we have today, forest floors were cleansed naturally by non-catastrophic fires.
Ancient tree-ring records from southwest U.S. suggest today’s megafires are truly unusual
Unprecedented study relies on more than 1,500 years of tree-ring data and hundreds of years of fire-scar records gathered from Ponderosa Pine forests
Today’s mega forest fires of the southwestern U.S. are truly unusual and exceptional in the long-term record, suggests a new study that examined hundreds of years of ancient tree ring and fire data from two distinct climate periods.
Researchers constructed and analyzed a statistical model that encompassed 1,500 years of climate and fire patterns to test, in part, whether today’s dry, hot climate alone is causing the megafires that routinely destroy millions of acres of forest, according to study co-author and fire anthropologist Christopher I. Roos, Southern Methodist University, Dallas.
The researchers found that even when ancient climates varied from each other — one hotter and drier and the other cooler and wetter — the frequencies of year-to-year weather patterns that drive fire activity were similar.
The findings suggest that today’s megafires, at least in the southwestern U.S., are atypical, according to Roos and co-author Thomas W. Swetnam, the University of Arizona. Furthermore, the findings implicate as the cause not only modern climate change, but also human activity over the last century, the researchers said.
“The U.S. would not be experiencing massive large-canopy-killing crown fires today if human activities had not begun to suppress the low-severity surface fires that were so common more than a century ago,” said Roos, an assistant professor in the SMU Department of Anthropology.
Today’s extreme droughts caused by climate change probably would not cause megafires if not for a century of livestock grazing and firefighting, which have combined to create more dense forests with accumulated logs and other fuels that now make them more vulnerable than ever to extreme droughts. One answer to today’s megafires might be changes in fire management.
“If anything, what climate change reminds us is that it’s pretty urgent that we deal with the structural problems in the forests. The forests may be equipped to handle the climate change, but not in the condition that they’re currently in. They haven’t been in that condition before,” Roos said.
Roos and Swetnam, director of the University of Arizona Laboratory of Tree-Ring Research, published their findings in the scientific journal The Holocene.
Study combines fire-scar records and tree-ring data of U.S. southwest
This new study is based on a first-of-its-kind analysis that combined fire-scar records and tree-ring data for Ponderosa Pine forests in the southwest United States.
Earlier research by other scientists has looked at forest fire records spanning the years from 1600 to the mid-1800s — a climate period known as the Little Ice Age — to understand current forest fire behavior. Those studies have found that fires during the Little Ice Age occurred frequently in the grasses and downed needles on the surface of the forest floor, but stayed on the floor and didn’t burn into the canopies.
Critics dispute the relevance of the Little Ice Age, however, saying the climate then was cooler and wetter than the climate now. They say a better comparison is A.D. 800 to 1300, known as the Medieval Warm Period, when the climate was hotter and drier, like today’s.
Scientists who favor that comparison hypothesize that forest fires during the Medieval Warm Period probably were similar to today’s megafires and probably more destructive than during the Little Ice Age.
Tree rings and fire scars provide the evidence for moisture, drought and burn activity
Scientists rely on tree rings not only to calculate a tree’s age, but also to determine wet and dry weather patterns of moisture and drought. Similarly, scientists’ best evidence for fire activity is the scarring on tree rings that dates the occurrence of fires. While tree-ring data for climate are available for long time periods, annual forest fire records don’t yet exist for the Medieval Warm Period.
In response to the need for data, Roos and Swetnam tested the Medieval Warm Period hypothesis by calibrating a statistical model that combined 200 years of Little Ice Age fire-scar data and nearly 1,500 years of climate data derived from existing tree rings. With that they were able to predict what the annual fire activity would have been almost 1,500 years ago.
They discovered that the Medieval Warm Period was no different from the Little Ice Age in terms of what drives frequent low-severity surface fires: year-to-year moisture patterns.
“It’s true that global warming is increasing the magnitude of the droughts we’re facing, but droughts were even more severe during the Medieval Warm Period,” Roos said. “It turns out that what’s driving the frequency of surface fires is having a couple wet years that allow grasses to grow continuously across the forest floor and then a dry year in which they can burn. We found a really strong statistical relationship between two or more wet years followed by a dry year, which produced lots of fires.”
Modeling of tree-ring and fire-scar data can be applied to any locale
The research, “A 1416-year reconstruction of annual, multidecadal, and centennial variability in area burned for ponderosa pine forests of the southern Colorado Plateau region, Southwest USA,” was funded by the International Arid Lands Consortium.
“The best way to look at how fires may have varied — if climate were the only driver — is to do this type of modeling,” Roos said. “Our study is the first in the world to go this far back using this methodology. But this method can be used anyplace for which there is a fire-scar record.”
The study’s tree-ring-derived climate data are from the southern Colorado Plateau, a region that includes the world’s largest continuous stand of Ponderosa Pine stretching from Flagstaff, Ariz., into New Mexico. Large Ponderosa Pine forests have existed in the area for more than 10,000 years.
Fire-scar data for the region go back as far as the 1500s, but are most prevalent during the Little Ice Age period. Fire scientists have analyzed fire-scars from hundreds of trees from more than 100 locations across the Southwest. All fire-scar data are publically available through the International Multiproxy Paleofire Database, maintained by the federal National Oceanic and Atmospheric Administration’s paleoclimatology program.
Ancient fires were frequent, but didn’t burn the forest canopy
Fire scientists know that in ancient forests, frequent fires swept the forest floor, often sparked by lightning. Many of the fires were small, less than a few dozen acres. Other fires may have been quite large, covering tens of thousands of acres before being extinguished naturally. Fuel for the fires included grass, small trees, brush, bark, pine needles and fallen limbs on the ground.
“The fires cleaned up the understory, kept it very open, and made it resilient to climate changes because even if there was a really severe drought, there weren’t the big explosive fires that burn through the canopy because there were no fuels to take it up there,” Roos said. “The trees had adapted to frequent surface fires, and adult trees didn’t die from massive fire events because the fires burned on the surface and not in the canopy.”
Today’s huge canopy fires are the cumulative result of human activity
The ancient pattern of generally small, frequent fires changed by the late 1800s. The transcontinental railroad had pushed West, bringing farmers, ranchers, cattle and sheep. Those animals grazed the forest floor, consuming the grasses that fueled small fires but leaving small saplings and brush, which then grew up into dense, mature bushes and trees. In addition, the U.S. began to restrict the traditional land use of the region’s Native American communities, including confining them to reservations. This removed another source for frequent surface fires in the forests — burning by Native Americans for horticulture and hunting.
By the early 20th century, the U.S. Forest Service had been established, and fighting fires was a key part of the agency’s mission. Without continuous fuel, fires on the forest floor ceased.
“Many of our modern forests in central Arizona and New Mexico haven’t had a fire of any kind on them in 130 or 140 years,” Roos said. “That’s very different from the records of the ancient forests. The longest they would have gone without fires was 40 or 50 years, and even that length of time would have been exceptional.”
The research reported in The Holocene is the basis for a new four-year, $1.5 million grant from the National Science Foundation in which Roos and Swetnam are co-principal investigators. That project will examine how human activities have changed forests and forest fires over the past 1,000 years of Native American occupation, as well as the influence of droughts during the Medieval Warm Period and Little Ice Age in New Mexico’s Jemez Mountains. — Margaret Allen
SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smuresearch.com.
The native Americans regularly burned the forests. This is why long leaf pine was the primary wood of east Texas; it was highly resistant to forest fire. It was the more recent immigrants who stopped the annual or biannual fires. The result is that a lot of burnables end up building up. Furthermore, it’s become more and more difficult to give your forest a light burn due to EPA considerations.
This was done throughout the US. The intention was to make the land better for hunting deer and growing corn. Nowadays we could probably do something similar with diesel powered hydraulic equipment but at the time, burning was very effective.
When Lewis and Clark crossed the country, the forests in the Pacific NW were park like due to the regular burns. If you try this now you end up having to hack through incredible berry tangles.
Gail Combs says:
May 18, 2012 at 11:38 am
“Sorry Crosspatch, logging interest are not that stupid. A controlled burn is used to clean up the under-story, return nutrients to the ground and to prevent the build up of material that can cause really destructive fires. I can drive along the highway near my place and point out all the controlled burn sites here in North Carolina.”
Unfortunately I have seen cases here in WY where in the national forest, loggers have NOT cleaned up toppings and debris after logging on public lands whether due to negligence on their part, since it is not their land/trees, negligence on the part of the Forest Service in rules or enforcement of rules, I do not know. However, it would seem that all the good done relative to fire prevention from thinning out the trees is negated by leaving the trimmings behind on the forest floor.
Jim G says: @ur momisugly May 18, 2012 at 1:09 pm
…..Unfortunately I have seen cases here in WY where in the national forest, loggers have NOT cleaned up toppings and debris after logging on public lands whether due to negligence on their part, since it is not their land/trees, negligence on the part of the Forest Service in rules or enforcement of rules, I do not know. However, it would seem that all the good done relative to fire prevention from thinning out the trees is negated by leaving the trimmings behind on the forest floor.
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It depends on the state and it depends on the contract with the land owner. In New Hampshire they have to clean up their messes. In NC it is up to what is in the contract. However with a coal plant that also burns wood not far away it pays to chip the trash and haul it to the coal plant to be bought as “bio-fuel”
Around here it is the individual land owners who thin and burn to get the best “crop” of pine.
Hot fires don’t leave a lot of tree rings.
North America didn’t have a forest fire suppression program for the last 1400 years, so there wasn’t a fuel buildup issue like we have today, forest floors were cleansed naturally by non-catastrophic fires.
You are dead wrong about that, Anthony. In fact, it was anthropogenic (human-set) fires that prevented megafires, and not just for 1400 years but for ten times that long.
Large Ponderosa Pine forests have existed in the area for more than 10,000 years.
Human beings have existed in the area for at least 13,500 years and probably 15,500 years. That means humans predated the pine trees by many millenia. Look it up.
When human beings arrived on this continent, they brought with them ~1.8 million years of burning experience. Practice makes perfect.
The Precontact (before Euro-American) forest development pathways were mediated by frequent, purposeful, anthropogenic fires deliberately set by skilled practitioners, informed by long cultural experience and traditional ecological knowledge in order to achieve specific land management objectives. At a landscape scale the result was maintenance of an (ancient) anthropogenic mosaic of agro-ecological patches. In the absence, over the last 200 years, of purposeful anthropogenic fires, the anthropogenic mosaic has been invaded and obscured by thickets.
The open, park-like pinenut orchard/forest that existed in Precontact times in the Southwest was constructed by people. Proof is that nowhere are such forest structures arising “naturally” today.
Megafires are caused by quantity and continuity of fuels. Lightning fires are entirely inadequate at reducing biomass or breaking up fuel continuity.
The First Residents were not so stupid as to allow catastrophic fires to destroy their means of survival. They took precautions by burning in cool seasons. That fact has been well established.
When “scientists” deny historical human influences on the environment, they display extreme cultural bigotry tantamount to racism. It is Victorian junk science, something we supposedly advanced beyond 160 years ago, but it hangs on like boil on the neck of science.
Please try to acknowledge history. Try not to think that you, today, are the first human being ever to walk the earth. Don’t be a cultural bigot. The truth will set you free.
And by the way, to those of you who think fire suppression is a bad thing, please underestand that without it the entire Western US would be uninhabitable. Chico, for instance, would be scorched earth wasteland without a living soul in it.
The Australian eucalypt forests were managed by the aboriginals for 40k years prior to European settlement. Their management tool, fire, was administered with the experience gained in countless generations of “fire stick farming”. This practice not only made the bush more open and easier for hunting, but promoted the growth of “green pick”, new grass attractive to kangaroos and other target species.
The progressive closure of public forest land in poorly managed National Parks, with the unnatural exclusion of fire, led to intense wild fires. These fires culminated in the Victorian “Black Saturday Fires” of February 2009, which cost 173 lives. Thankfully there now seems to be an increased awareness that regular fuel reduction burning is essential for public safety.
Mike Dubrasich and Bob in Castlemaine, that information on the prehistoric use of fire was covered in my Anthro class forty years ago so it is not exactly new knowledge either.
Thanks for bringing it up.
Bob in Castlemaine, some parts of the country were burned by Aboriginal people pre-European settlement – but most were not. There simply weren’t that many people living on this vast continent, and burning was small scale and localised. The vast forests of the Great Dividing Range, for example, were not routinely burned, because (a) very few people lived there; and (b) just like today, it is extremely difficult to control a fire in that rugged terrain once it gets started.
There is a lot of ‘noble savage’ mythology around about Aboriginal burning, which undoubtedly occurred, but was dwarfed by the massive wildfires which started and finished naturally every summer, just as they do today, despite a much larger population and the availability of firefighting resources.
Mark Twain describes accidentally starting a wild fire (somewhere out west) in “Roughing It.” It started from their cooking fire, as they walked down to a lake to get water. After a brief time spent attempting to halt the spread, he and his pal had to flee out onto a lake. As night came on they could see the fire had gone over the nearby hills and was spreading up the more distant ranges. Having blackened all the nearby landscape, the next day they decided to quit camping and try something else.
I now want to go back and reread that brief description. It was only a few pages. As I recall, he didn’t feel all that guilty, and didn’t flee to escape the wrath of Smokey the Bear. I would guess it occurred 1870-1880.
What does this prove? Nothing much, unless it is that fire spreads very swiftly out west. Also that it can be dangerous to associate with writers.
Johanna refers to “‘noble savage’ mythology around about Aboriginal burning”.
It is true that there was little burning in the alpine country, but that was more because access was seasonal and the open nature of alpine vegetation meant there was little point in doing so. But there is evidence in the numerous eyewitness accounts of famous early explorers and settlers to substantiate that aboriginal burning was wide spread elsewhere throughout the forests and woodland of Australia. This reference identifies just a few of the more distinguished amongst the many people of the time who documented what they saw; they include Captain James Cook, Sir Joseph Banks, Matthew Flinders, Governor Arthur Phillip, Gregory Blaxland, Allan Cunningham, Captain Charles Sturt and Major Thomas Mitchell (see pages 2 to 5).
Even today aboriginal burning is still practiced in parts of northern Australia. The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby to justify the prevention of rational fire management regimes. Like so much in contemporary post normal science, it not based on evidence but is justified almost solely on the basis of the so-called “precautionary principle”.
Bob in Castlemaine is absolutely correct when he says, The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby…
It is racist myth used to bolster their false assertion that human beings are toxic to the environment.
The facts are clearly that technological man and nature have co-existed since the evolutionary appearance of Homo erectus 1.8 million years ago. We are and always have been the caretakers of nature.
But a certain virulent philosophy seeks to tear down man, to paint man as a toxic disease on the Planet. They assert that man is evil, that the human population must be heavily culled, and that the survivors must be herded into concentration camps by “wise” eco-masters.
It’s just the same old ugly fascist-communism under a green hat.
Despite the horrors wrought by that philosophy in the 20th Century, it has not gone away.
That’s why it is essential to point it out and deconstruct that philosophy when it rears its ugly head, whether it takes form as bogus notions of human-caused climate change or deliberate erasure of human history.
PS to Gail: how did common knowledge 40 years ago (indeed for all of human history) become lost? Don’t tell me people just forgot. No, there has been an insidious campaign, to destroy knowledge for despicable anti-human purposes, that has been waged on society.
http://jennifermarohasy.com/2009/03/victorian-bushfires-the-result-of-human-folly/
Pamela Gray says on May 18, 2012 at 6:06 am:
“There was way more carbon soot in the air and on the ground in forests and grasslands prior to industrialization. Because of human impacts, there now is way less.”
I ask you this question: Since 1900, where have the many billions (and billions and billions!) of pounds of fine particles of rubber and asphalt gone? The short simple answer is anywhere and everywhere.
I passenger care tire with an A treadwire rating will shed about a pound of rubber over its lifetime. Bulk rubber and asphalt do not easily catch fire. Very fine particles of rubber (known as rubber dust) are a fire hazard in industrial operations, and methods are undertaken to control and prevent accummlation of it in plants especially near electrical motors or equipment were a spark can occur.
Fine particles of rubber and asphalt could act as acelerants and might contribute to ferocity of wild fires in Southern Cailfronia. Home owners should wash any these particles off the roof of their house before the start fire season.
Modern synthetic rubbers are not degraded upon exposure to air and sunlight and to microbes due to addtion of UV protectents, anti-oxidants and anti-microbial agents.
To check for road dust in urban area or near alarge roadway, which is comprised of particles of soil, rubber, asphalt, sand from concrete,etc, dab a Post-It on any horizontal surface (e.g., the top of a car) after few days of no rain. Examine the blakened sticky under modest magnification (ca. 30-50x). The black flat flecks are rubber, the amorous paricles are from asphalt. The highly-refractory opaque spheres are sand from concrete. The flat, highly reflective small flecks re mica.
These are the particles you can see. There is class of particles (i.e., PM 2.5) you can not see unless you have compound microsope. I read that children that live major highways and commuter routes have higher rate of asthma than children who that do not live near these.
Harold Pierce Jr says:
May 19, 2012 at 4:18 pm
I read that children that live major highways and commuter routes have higher rate of asthma than children who that do not live near these.
Where did you read that? A sister of mine was born in bucolic Clackmannanshire, Scotland with asthma circa 1958.
Bob in Castlemaine says:
May 19, 2012 at 6:28 am
Johanna refers to “‘noble savage’ mythology around about Aboriginal burning”.
It is true that there was little burning in the alpine country, but that was more because access was seasonal and the open nature of alpine vegetation meant there was little point in doing so. But there is evidence in the numerous eyewitness accounts of famous early explorers and settlers to substantiate that aboriginal burning was wide spread elsewhere throughout the forests and woodland of Australia. This reference identifies just a few of the more distinguished amongst the many people of the time who documented what they saw; they include Captain James Cook, Sir Joseph Banks, Matthew Flinders, Governor Arthur Phillip, Gregory Blaxland, Allan Cunningham, Captain Charles Sturt and Major Thomas Mitchell (see pages 2 to 5).
Even today aboriginal burning is still practiced in parts of northern Australia. The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby to justify the prevention of rational fire management regimes. Like so much in contemporary post normal science, it not based on evidence but is justified almost solely on the basis of the so-called “precautionary principle”.
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Bob, if you have ever flown up or down the Great Dividing Range, which extends for thousands of miles just inside the east coast of Australia, you will know that it is hardly an open alpine environment for the most. It is mainly incalculable billions of eucalypts which form an impenetrable barrier from the air. A few thousand Aborigines, dotted here and there, could not possibly have impacted that environment through burning without self immolating, and it just never happened.
I have never disputed that burning occurred, but I strongly dispute that the reason for huge bushfires which leave nothing but a pile of ash is the cessation of Aboriginal burning. The lightning strikes which caused the Canberra bushfires of 2003 (which I experienced) occurred in rugged and heavily forested country in the mountains. No-one could seriously suggest that lightning strikes and fires like that never occurred pre-European settlement. The reason this is now a political issue is that people live near the forest boundaries these days, and their property (and sometimes lives, sadly) are destroyed.
I absolutely agree that if people want to live in these places, they need to keep the land around their home cleared and so on. But anyone who has ever seen a 30 metre high wall of fire driven by hot westerlies (as I have) might share my view that living in these locations carries a small, but uncontrollable, risk of losing everything and/or being burned to a crisp, no matter what human interventions there are.
Yeh. The grass is always greener and the fires less catastrophic in times past. Horse apples and cow pies.
And of course one only has to see how many types of tree and shrub, particularly in Australia, (I don’t know about the US flora), actually REQUIRE a good dose of heat for seed germination.
clipe says on May 19, 2012 at 4:58 pm:
Harold Pierce Jr says:
May 19, 2012 at 4:18 pm
I read that children that live major highways and commuter routes have higher rate of asthma than children who that do not live near these.
Where did you read that? A sister of mine was born in bucolic Clackmannanshire, Scotland with asthma circa 1958
I remember reading some time ago an article in the Vancouver Sun that investigators have found that asthma were more prevalent in young children living in dense cities near high traffic areas than those who living suburban or rural areas
ATTN: clipe
What type of fuel was used for heating and cooking in Clackmannanshire? Were the house well ventilated? Was the air smokey?
AndyG55 (from down-under) says:
May 19, 2012 at 5:59 pm
And of course one only has to see how many types of tree and shrub, particularly in Australia, (I don’t know about the US flora), actually REQUIRE a good dose of heat for seed germination.
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Not only that, Andy, as I said above – catastrophic bushfires are probably the main reason for the dominance of Eucalypts in Australia. They regenerate quickly after fire and then poison the soil around them with eucalyptus oil and other toxins to kill off the opposition.
I can’t speak for US forests, but the notion that devastating fires are a new thing is utter nonsense in Australia.
For those interested in a comprehensive history of fire in the Australian bush, can I suggest have a read of Burning Bush by Stephen Pyne.
USDA forest service published Fire Management Today in 2000 (#3) on the frequent use of low-level fires by native americans prior to 1900. http://www.fs.fed.us/fire/fmt/fmt_pdfs/fmn60-3.pdf
“Indian fire use, mostly for peaceful purposes, was so extensive that it shaped ecosystems across North America.”
In South Korea Visit, Obama Visits Border and Warns North
PANMUNJOM, South Korea — President Obama warned North Korea on Sunday that its threats and provocations would only deepen its international isolation and jeopardize the resumption of American food aid, and he called on the North to scrap its plans to launch a satellite next month.
Squinting through binoculars from an observation post at the demilitarized zone between North and South Korea, Mr. Obama got a firsthand look at North Korea. The North, with a new leader in place, briefly tantalized the United States weeks ago by raising the possibility of ending the standoff over its nuclear program, only to resume its usual defiance with the recent satellite announcement.