Here is just one more indication that despite what some would like you to believe, the MWP was not a regional “non event”.
From a University of Arizona press release,
Giant Sequoias Yield Longest Fire History from Tree Rings
California’s western Sierra Nevada had more frequent fires between 800 and 1300 than at any time in the past 3,000 years, according to a new study led by Thomas W. Swetnam, director of UA’s Laboratory of Tree-Ring Research.
A 3,000-year record from 52 of the world’s oldest trees shows that California’s western Sierra Nevada was droughty and often fiery from 800 to 1300, according to a new study led by University of Arizona researchers.
Scientists reconstructed the 3,000-year history of fire by dating fire scars on ancient giant sequoia trees, Sequoiadendron giganteum, in the Giant Forest of Sequoia National Park. Individual giant sequoias can live more than 3,000 years.
“It’s the longest tree-ring fire history in the world, and it’s from this amazing place with these amazing trees.” said lead author Thomas W. Swetnam of the UA. “This is an epic collection of tree rings.”
The new research extends Swetnam’s previous tree-ring fire history for giant sequoias another 1,000 years into the past. In addition, he and his colleagues used tree-ring records from other species of trees to reconstruct the region’s past climate.
The scientists found the years from 800 to 1300, known as the Medieval Warm Period, had the most frequent fires in the 3,000 years studied. Other research has found that the period from 800 to 1300 was warm and dry.
“What’s not so well known about the Medieval Warm Period is how warm it was in the western U.S.,” Swetnam said. “This is one line of evidence that it was very fiery on the western slopes of the Sierra Nevada – and there’s a very strong relationship between drought and fire.”
Droughts are typically both warm and dry, he added.
Knowing how giant sequoia trees responded to a 500-year warm spell in the past is important because scientists predict that climate change will probably subject the trees to such a warm, dry environment again, said Swetnam, a UA professor of dendrochronology and director of UA’s Laboratory of Tree-Ring Research.
During the Medieval Warm Period extensive fires burned through parts of the Giant Forest at intervals of about 3 to 10 years, he said. Any individual tree was probably in a fire about every 10 to 15 years.
The team also compared charcoal deposits in boggy meadows within the groves to the tree-ring fire history. The chronology of charcoal deposits closely matches the tree-ring chronology of fire scars.
The health of the giant sequoia forests seems to require those frequent, low-intensity fires, Swetnam said. He added that as the climate warms, carefully reintroducing low-intensity fires at frequencies similar to those of the Medieval Warm Period may be crucial for the survival of those magnificent forests, such as those in Sequoia and Kings Canyon National Parks.
Since 1860, human activity has greatly reduced the extent of fires. He and his colleagues commend the National Park Service for its recent work reintroducing fire into the giant sequoia groves.
The team’s report, “Multi-Millennial Fire History of the Giant Forest, Sequoia National Park, California, USA,” was published in the electronic journal Fire Ecology in February. A complete list of authors and funding sources is at the bottom of this story.
To study tree rings, researchers generally take a pencil-sized core from a tree. The oldest rings are those closest to the center of the tree. However, ancient giant sequoias can have trunks that are 30 feet in diameter – far too big to be sampled using even the longest coring tools, which are only three feet long.
To gather samples from the Giant Forest trees, the researchers were allowed to collect cross-sections of downed logs and standing dead trees, he said. It turned out to be a gargantuan undertaking that required many people and many field seasons.
“We were sampling with the largest chain saws we could find – a chain-saw bar of seven feet,” he said. “We were hauling these slabs of wood two meters on a side as far as two kilometers to the road. We were using wheeled litters – the emergency rescue equipment for people – and put a couple hundred pounds on them.”
To develop a separate chronology for past fires, co-authors R. Scott Anderson and Douglas J. Hallett looked for charcoal in sediment cores taken from meadows within the sequoia groves.
“We can compare the charcoal and tree-ring fire records. It confirms that the charcoal is a good indicator of past fires,” Swetnam said.
Such charcoal-based fire histories can extend much further into the past than most tree-ring-based fire histories, he said. The charcoal history of fire in the giant sequoia groves extends back more than 8,000 years.
Increasingly, researchers all over the world are using charcoal to reconstruct fire histories, Swetnam said. Many scientists are analyzing the global record of charcoal to study relationships between climate, fire and the resulting addition of carbon dioxide to the atmosphere.
Swetnam’s co-authors are Christopher H. Baisan and Ramzi Touchan of the University of Arizona; Anthony C. Caprio of Sequoia and Kings Canyon National Parks in Three Rivers, Calif.; Peter M. Brown of the Rocky Mountain Tree-Ring Research and Colorado State University in Fort Collins; R. Scott Anderson of Northern Arizona University in Flagstaff; and Douglas J. Hallett of the University of Calgary in Alberta, Canada.
The National Park Service, the U.S. Geological Survey, Mountain Home Demonstration State Forest and Calaveras Big Trees State Park provided funding.
h/t to Dr. Leif Svalgaard
http://www.wrcc.dri.edu/enso/ensofaq.html
Seems that ENSO has been on about the same cycle for a long time then.
That part of California would be drier during La Nina. Warmer air temperatures with ocean temperatures lagging would result in La Nina’s having a relatively larger spread between water and air temps producing a stronger effect even with weak La Nina’s. Hence more severe and frequent drought in certain regions. Colder air temps with ocean temps lagging would increase the effect of weak to moderate El Nino’s similar to recent conditions.
Or something like that.
peace,
Tim
Given that there were diverse cultures among Native Americans, I have no doubt that there were Millions here before the arrival of Columbus. But not necessarily
no Europeans either. There were seafaring cultures long before. I think we have
idea of what was here before, and I do know that fire setting to improve elk and
deer habitat was/is still a common practice….
Wren (19:50:58) :
The data shows otherwise.
Sorry for the eggheads that say their numbers are better than the real data.
Next?
Sorry. I keep forgetting that you folks are not historical landscape geographers, ethno-ecologists, paleobotanists, or forest historians. I mean, very few people are familiar with that stuff, and I should not expect it to be common knowledge. I apologize.
If you are interested in the lastest findings in those fields, please visit my History of Western Landscapes site:
http://westinstenv.org/histwl/
Here is a good reference on historical population estimates:
Denevan, Wm. 1976. The Native Population of the Americas in 1492. Univ. of Wisconsin Press. A compilation of historical demographic analyses by scholars including Denevan, Woodrow Borah, and William T. Sanders. Despite being over 30 years old, Native Populations of the Americas in 1492 is still considered to contain the best estimates to date of pre-Columbian populations.
Denevan’s own analysis and synthesis of the work of Borah, Henry Dobyns, Wilbur R. Jacobs and others leads him to estimate that the population of the New World in 1492 was at least 57,000,000 people. That count exceeds the estimated population of much of contemporaneous Europe.
See also:
Blackburn, Thomas C. and Kat Anderson, eds. 1993. Before The Wilderness: Environmental Management by Native Californians. Malki Press – Ballena Press.
Thomas M. Bonnicksen, M. Kat Anderson, Henry T. Lewis, Charles E. Kay, and Ruthann Knudson. 1999. Native American influences on the development of forest ecosystems. In: Szaro, R. C.; Johnson, N. C.; Sexton, W. T.; Malk, A. J., eds. Ecological stewardship: A common reference for ecosystem management. Vol. 2. Oxford, UK: Elsevier Science Ltd: 439-470.
Stewart, Omer C. Forgotten Fires — Native Americans and the Transient Wilderness. 2002. Edited and with Introductions by Henry T. Lewis and M. Kat Anderson. University of Oklahoma Press.
Bonnicksen, Thomas M., 2000. America’s Ancient Forests–From the Ice Age to the Age of Discovery. John Wiley and Sons.
Anderson, M. Kat. 2005. Tending the Wild: Native American Knowledge and the Management of California’s Natural Resources. Univ. Calif. Press.
Kay, Charles E., and Randy T. Simmons, eds. 2002. Wilderness and Political Ecology: Aboriginal Influences and the Original State of Nature. University of Utah Press.
Does anyone have a link to an IPCC study showing CO2 levels from 1000AD to present day?
I still fail to understand how tree rings can be considered “thermometers” of climate history. There are so many variables involved in the growth and survival of trees, how can we be sure their rings describe what scientists say they do? Furthermore, rudimentary research design and methodology would point out that Briffa’s 12 magic Yamal trees are not a statistically valid sample size to base the whole theory of AGW upon. This is common sense… and yet the unelected UN bureaucrats are already trying to introduce carbon taxes around the world? Will we need to rebel and overthrow governments to rid ourselves of this carbon trading fraud? Close down the UN before we end up under a totalitarian new world order.
REPLY: In this case they aren’t being considered “thermometers” only as yearly seasonal recorders with char marks at certain years. – Anthony
Amino Acids in Meteorites (19:32:36) : And if American Indians did start forest fires why did they start more of them during the Medieval Warm Period, 800 to 1300, than at any other time?
1. Perhaps the frequency did not change, but the scarring is a function of fuel density. More fuels, more scarring. Many (most) light-burning fires left no scar. It could be that increased/decreased biomass growth was a function of something other than temperature.
2. Perhaps the fire frequency was a function of population density, cultural practices innovations, or other human-based factors that had nothing to do with temperature, such as war, peace, displacement, entrenchment, food preference shifts, food availability changes, evolution in customs, advances in ecological knowledge, population growth, etc.
Are “historical acres under cultivation” in Europe and the Middle East a proxy for temperature? People are not machines. We are not robots impelled by climate. We are innovative, adaptive, and have always been culturally evolving.
And again, human beings have controlled the fire regimes wherever we have lived (except the Arctic where there is no fuel on the landscape) since we evolved in Africa. Homo erectus possessed fire. Hominid use of fire goes back 2 million years.
John F. Hultquist (19:59:56) : “Picture Gallery of Trees and Tree Rings (Univ. of Tenn., Knoxville)…”
Nifty, John!
Mike D. (20:38:08) :
“Sorry. I keep forgetting that … very few people are familiar with that stuff”
And we’re supposed to consider you a logical person, because?
Not A Carbon Cow (20:29:15):
Human-set fires were so frequent that they altered the fuels. Infrequent lightning fires burned in culturally modified landscapes and so behaved much like anthropogenic fires, following the same fire patterns in the established anthropogenic mosaic. Human-set fires outnumbered lightning fires by many orders of magnitude. See:
Kay, Charles E. Are Lightning Fires Unnatural? A Comparison of Aboriginal and Lightning Ignition Rates in the United States. 2007. IN R.E. Masters and K.E.M. Galley (eds.) Proceedings of the 23rd Tall Timbers Fire Ecology Conference: Fire in Grassland and Shrubland Ecosystems, pp 16-28. Tall Timbers Research Station, Tallahassee, FL.
Question: Where did the data for the “Battle of the Graphs” come from? Would love to see references to the peer reviewed, validated data.
Interesting article…thanks!
Mike D. (20:38:08) :
Sorry. I keep forgetting that you folks are not historical landscape geographers, ethno-ecologists, paleobotanists, or forest historians. I mean, very few people are familiar with that stuff, and I should not expect it to be common knowledge. I apologize.
>>
You are right, I’m not familiar. I am familiar with estimates in the early 1900’s being a million or two. then by the middle of the century they were 30 or 40. Now they are up to 100. What I notice is that with each increase the decline to known numbers when decent records start is blamed on disease, mistreatment and displacement by white man. I’m not saying the conflict with Europeans influx wasn’t hard on them, or that there were no epidemics due to disease, just that the higher the number goes the more words like “genocide” and “fault” get thrown into the equation.
Further native societies were very primitive. They were hunter/gatherer. No metal working, no wheels, no ploughs, no agriculture, no livestock. Until Cortez they didn’t even have horses. The range even a small tribe would have to hunt over to sustain themselves is large, and I just don’t buy 57 million being sustained with bows and arrows.
Mike D., I checked out the link you provided and noted with interest the following entry in your list of publications:
An Urgent Signal for the Coming Ice Age by Peter John Faraday Harris in Paleobotany and Paleoclimatology
Aside from that, it strikes me as preposterous to suggest that all, or even most, of the fires in the sequoia groves were man-made. These are fire-dependent trees, and their evolutionary history necessarily predates human existence, especially any human presence in North America. So how did they become fire-dependent if there were no humans around to start the fires?
The population densities of Native Americans encountered by the early colonists and explorers are totally inconsistent with the 50 million plus figure you suggest. Frankly, this strikes me as delusional, but thanks for playing.
davidmhoffer (21:13:10): You are right, I’m not familiar. … Further native societies were very primitive.
Beware of the cultural bigotry so ingrained in our modern society. Read the refs I provided. Visit the site I linked to. Study it up. I think if you examined the literature, you would come to a very different conclusion. We are an ancient species, and we’ve always been clever and capable.
Here’s a controversial paper you all might enjoy (because Gavin hates it):
Ruddiman, William F. 2003. The Anthropogenic Greenhouse Era Began Thousands of Years Ago. Climatic Change 61: 261–293, 2003.
http://stephenschneider.stanford.edu/Publications/PDF_Papers/Ruddiman2003.pdf
If modern land use can affect the temperature, then why not ancient land use, too?
For what it’s worth department. My wife and I hiked in Big Basin Redwood Park in Santa Cruz, CA after reading about Climategate. My recollection is that the 7′ cut of the redwood tree that was time dated by the Rangers had a much longer period during the “Medieval Warm Period” than during recent time periods. There was no obvious evidence of fires but the size and timing of the tree rings clearly showed that the rings were larger (for what that means) during the middle ages. Someone with knowledge and expertise in this area could give feedback and analysis. If I could post a picture, I would.
Mike D. (20:38:08) :
“Sorry. I keep forgetting that you folks are not historical landscape geographers, ethno-ecologists, paleobotanists, or forest historians. I mean, very few people are familiar with that stuff, and I should not expect it to be common knowledge.”
Thank god for that. Give me real chemistry and physics science any day.
Mike D 18 55 01
Indeed humans have lived inthe Sierras for 10000+yrs. But don’t you find it curious that they would have concentrated their efforts particularly in the middle ages? Might it be that its harder to get a decent forest fire going during cold rainy periods than when it is particularly warm and dry? We only get large numbers of forest fires in Canada during hot dry spells. Also,nearly all fire are caused by lightning storms which develop and build up during hot summer days.
Mike D
Sorry, but as soon as I see the word “ethno-ecologist” I know what’s coming next, and I’m not buying it.
The Ents are moving indeed; running in fact, no one has ever seen them run faster. Nice dead tree ring entrails. Dead tree ring entrails to fight the soothsaying with other dead tree ring entrails. Sweet ironic twisted trunk of science that is! I guess it’s not just Mann hiding the decline but also ignoring the fires! That’s what Mann, et. al., get for cherry picking. Fighting Mann, et. al.’s fire with natural fire! Gotta love it when the natural counter evidence is so clear and damning. Yes, these logs would make excellent material for Beavers dams. Damn, that’s a damned pun. [:)]
I remember reading an interesting article, possibly in the Smithsonian magazine but I don’t really remember. It concerned the rediscovery of the management of California oaks in the Sierra foothills by Native Americans through the use of controlled fires. Apparently the perceived quality of the trees had been deteriorating, with the trees growing closer together, staying much smaller, and producing far fewer acorns.
It was finally recognized that it was the “protection” of the trees that was causing the problem. A large study, including of Indian oral traditions, revealed that the natives had been consciously managing the oaks for hundreds or thousands of years to maximize acorn production since that was an important food source. Interestingly, there existed a very strong concept of property rights, very similar to Western European capitalist tradition. This recognition of ownership ensured that families or clan, guaranteed by tribal law or custom to the (literal) fruits of their labors, would have the incentive to engage in such a long-term endeavor, rather than hunt and gather. The lone oak trees spaced out over grassy hillsides surrounded by fallen acorns are a legacy of that time. The dense patches of scrub oaks choking each other out are in those areas that have reverted back to their natural state.
So yes, I believe it’s likely that humans did regularly “set fires” when there was a tangible reward for doing so. I can’t think of any reason, though, why they would periodically set fire to a redwood forest. It’s an interesting claim, but setting fires for the hell of it, on a regular basis, sounds like reaching to me.
Mike D. (21:06:08) :
Not A Carbon Cow (20:29:15):
“Human-set fires were so frequent that they altered the fuels. Infrequent lightning fires burned in culturally modified landscapes and so behaved much like anthropogenic fires, following the same fire patterns in the established anthropogenic mosaic. Human-set fires outnumbered lightning fires by many orders of magnitude. See:
Kay, Charles E. Are Lightning Fires Unnatural? A Comparison of Aboriginal and Lightning Ignition Rates in the United States. 2007. IN R.E. Masters and K.E.M. Galley (eds.) Proceedings of the 23rd Tall Timbers Fire Ecology Conference: Fire in Grassland and Shrubland Ecosystems, pp 16-28. Tall Timbers Research Station, Tallahassee, FL.”
===============================================
Mike,
No-one doubts people set fires. Your assertion was that ALL of the historical fires documented in redwood tree rings were anthropogenic in origin, and that given the rest of us weren’t studied forest rangers, you would have to remind us of this fact, although you were surprised to have to do so, because you forgot we weren’t all studied forest rangers.
Personally, I find it very hard to believe that the descendants of a population of individuals intelligent enough to spread throughout the Americas, producing the Clovis culture, producing burial mounds in Ohio, rock structured settlements on the East coast, being the contemporaries of the Anasazi, Incas, Aztecs, those who produced the Nazca lines etc., were stupid enough to attempt to farm in the forest when easily accessible low lying rich and abundant farmland lay just to the west and south.
You hooked me again, but I’m crashing for the night. I’ve checked the batteries in my smoke alarms in case one of my neighbors decides to burn my yard tonight. (Cow, et. all BS Research vol 2 issue 34, pages 45-47 “All charcoal is man made says Mike”)
DesertYote (18:14:36) :
I would be interested in finding out what the evidence is for unusual drought conditions. Can anyone help educate me?
The white arrows on the picture make it a bit difficult and you have to look closely.
Note where the arrow points locate the char marks in the growth rings? Now follow those growth rings with your eyes out past the arrows and you see how close together the rings are? If you look at where the tree rings are closer together that indicates slow growth because of lack of moisture. They match perfectly with the fire marks.
In between the arrows locating the char marks from fire, the growth rings are not as close together, meaning the tree grew faster during that time because it had more moisture.
This is an excellent tree to read and a great post, Leif and Anthony!
Robert Kral (21:18:01) said:
You are obviously unaware of the power of teleconnection!
Mike D – thanx for your insights. Much aprecciated.