Talk:Dendroclimatology

Untitled
This is TCO. I added a bunch of new content to make the page more content-rich and also to make it less focussed on temperature. I removed the divergence section as it (while interesting) is not central to a basic encyclopedia description of the field.

It still needs some work in formatting. I'm new to wiki and haven't figured out how to quickly and easily use the controls.

This is a big upgrade. Feel free to make it better. If someone comes in and reverts it, I will scream.71.246.149.92 19:15, 1 April 2007 (UTC)

I am so wiki-clueless (TCO). I want to go back and edit my submission. Maybe para by para. But it won't seem to let me. Is there some rule that there needs to be an intermediate editor or a time delay?71.246.149.92 19:23, 1 April 2007 (UTC)

TCO again. I figured out. Need to hit the button at the top "edit this page".71.246.149.92 19:29, 1 April 2007 (UTC)

Done for now
I'm done messing with it for now. Main need is to add specific citations to the science literature.

I have tried to use a neutral tone to describe the field. I am broadly speaking a climate science skeptic, but not a denier. —The preceding unsigned comment was added by 71.246.149.92 (talk) 21:42, 1 April 2007 (UTC).

The last sentence of the Collections difficulties section is immaterial. I will remove it. (Endpoint5 (talk) 01:42, 3 December 2016 (UTC))

hidden agenda
There is something very wrong about this wiki entry when the article is mostly about the subject's limitations and not the actual subject itself. It is obvious that by focussing on its limitations, this scientific field is being discredited by author(s) who do not like the contribution it plays in climate science and perhaps something else 124.168.232.150 (talk) 12:59, 19 November 2014 (UTC)

Divergence Problem's Importance
It is not clear why the divergence problem is significant. Am I correct to assume that divergence implies a decreased correlation between the tree ring indicators and the actual temperature? If that is true, then divergence creates uncertainty in temperature predictions using tree rings, and this should be state clearly. It would also help to link to relevant statistic pages. I'll take it on myself to update the page if no one else does, but I really hate releasing my awful grammar on the world.Jfischoff (talk) 13:28, 25 November 2009 (UTC)


 * The reason why the "divergence problem" is significant is this -- if tree ring indicators do not in fact correlate to temperature, then the whole "art" of dendroclimatology is called into question. It may be that dendroclimatology is in fact no more valid scientifically than was phrenology. This is the "elephant in the room".
 * Impacts of soil, microclimate, disease, competition from other trees, moisture, etc. can cause variations that overwhelm temperature. Temperature thus becomes just one of many variables -- none of which can be controlled for since we don't have records of what those variables were in the past.
 * Note that dendroclimatology is thus unlike dendrochronology which is simpler (count the rings, compare to other dating system like Radiocarbon dating) and which can be off by a few years here and there yet still be very accurate by using large numbers of trees from a wide amount of area. SunSw0rd (talk) 14:28, 5 December 2009 (UTC)


 * What SunSword said --Divergence is central to whether dendroclimatology can be used in the AGW "crisis" debate. It's absurd to argue that it is "not central to a basic encyclopedia description of the field" -- as "hide the decline" so vividly demonstrates. Restore it! Pete Tillman (talk) 16:56, 5 December 2009 (UTC)
 * Restore what? -Atmoz (talk) 18:58, 5 December 2009 (UTC)


 * Well (blush) someone already did. Oops. Could use an update, and pointers to the current controversy, though. --Pete Tillman (talk) 19:11, 5 December 2009 (UTC)


 * Do you think that the current kerfuffle has added anything of scientific value to our understanding of the problem? If so, pointers would be good. Please don't bother with newspapers William M. Connolley (talk) 20:06, 5 December 2009 (UTC)


 * Would you like a pointer to a video? Oh, sorry, that's for Mike Mann's page.... ;-] Pete Tillman (talk) 20:51, 5 December 2009 (UTC)

Article probation
Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see General sanctions/Climate change probation for full information and to review the decision. --TS 20:38, 2 January 2010 (UTC)

New paper on divergence problem
"Detecting evidence for CO2 fertilization from tree ring studies: The potential role of sampling biases"

GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 26, GB1025, 13 PP., 2012. doi:10.1029/2011GB004143

Key Points (from abstract):
 * Observed increases in tree ring widths may be caused by sampling biases
 * Standard sampling methods lead to spurious trends in historical growth rates
 * Reported increases in ring width may often not be due to CO2 fertilization

Interesting. --Pete Tillman (talk) 21:01, 20 March 2012 (UTC)


 * What a bizarre co-incidence. WUWT has exactly the same thing William M. Connolley (talk) 22:33, 20 March 2012 (UTC)


 * Could you comment on the substance of the paper, please? Thanks, Pete Tillman (talk) 14:48, 21 March 2012 (UTC)

Main|Divergence problem
Seems like in long periods of higher or rising temperatures there would be more trees in a given forest, competing for nutrients/sunshine and other resources. The number of trees is obviously not reflected in the tree rings of individual trees, and yet could offset what would be expected if the same number of trees were growing from period to period.186.188.177.231 (talk) 22:52, 21 April 2014 (UTC)

Warmth vs stem diameter
http://treephys.oxfordjournals.org/content/30/6/669.full

" The median values for height, stem diameter and all biomass measurements at elevated growth temperatures were always near 1 for evergreens, indicating that for every study that found increased growth with warming, there were a similar number that found a decrease (Figure 2A, B and F)."

That is to say that in some studies warmer trees would have narrower tree rings, in some studies. I do not know the implications of this for dendroclimatology, but it certainly looks problematical. Greglocock (talk) 04:06, 19 August 2014 (UTC)

New paper updates the Sheep Mountain bristlecone chronology
Changing climate response in near-treeline bristlecone pine with elevation and aspect, Environmental Research Letters Volume 9 Number 11. Open Access & CC-A licensing, so contents are available free-licensed for use here, if desired.

This is an update of Graybill’s bristlecone chronologies, which were prominently featured in MBH 98 and subsequent "hockey stick" temperature reconstructions. From the abstract:
 * "There is evidence for a climate-response threshold between approximately 60–80 vertical m below treeline, above which trees have shown a positive growth-response to temperature and below which they do not. Chronologies from 80 m or more below treeline show a change in climate response and do not correlate strongly with temperature-sensitive chronologies developed from trees growing at upper treeline."

Obvious implications for interpretations of tree-rings for paleocliamtology. Interesting work. --Pete Tillman (talk) 20:36, 5 December 2014 (UTC)


 * Dr. Salzer got a nice writeup in the Arizona Daily Star (November 30, 2014), [tucson.com/ua-science-a-place-of-discovery-and-education/image_71e72df6-7a4a-11e4-a914-43d379c3baf6.html] -- note this is a VERY balky interface, article is on p.14. Quotes:


 * "during the summers of 2013 and 2014 we have deployed hundreds of button-sized temperature recorders on bristlecones in four different mountain ranges in California and Nevada. These devices record temperature readings every hour for up to a year."

…


 * “By combining the temperature data from the recorders with high-precision computer mapping, we found that individual trees growing at least as close as 100 yards can experience large differences in temperature…." --Pete Tillman (talk) 07:44, 6 December 2014 (UTC)
 * Interesting paper, with specific proposals for refinements and improvements to dendroclimatology. It also points to an aspect of the divergence problem. Unfortunately, Pete, you seem to be introducing original research reflecting a denialist obsession with certain old studies when you write "This is an update of Graybill’s bristlecone chronologies, which were prominently featured in MBH 98 and subsequent "hockey stick" temperature reconstructions": no sign of that in this paper. Since Greybill seems to have published in 1985 then the pioneering Jacoby and D'Arrigo 1989 paper would seem more relevant as an early dendro reconstruction: the MBH studies less so as they were multiproxy. Good to see H as a dendro expert working away at improving the science. . dave souza, talk 12:19, 7 December 2014 (UTC)

Citations needed
A lot of uncited commentary in this article, improvements needed. The above paper could be one source, Jacoby & D'Arrigo 1997 might also be useful at least as historical context. . dave souza, talk 12:35, 7 December 2014 (UTC)

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Posting for Ohio State Global Climate Change class
This article explains the use of tree rings as a climate proxy fairly well. It does not go too far in depth about how exactly the data from trees is analyzed, but it does give basic information that tree ring width is best related to climate parameters, but isotope and chemical trace analysis can also give useful climate information. The article does not explicitly discuss the assumptions made during processes of dendroclimatology, but rather cites certain expected behaviors, such as trees in certain areas are expected to respond more strongly to particular factors. I think the article could do a better job of explicitly citing the assumption that are made to do this type of data analysis. It does, however, do a good job at pointing out the strengths and weakness of using this kind of proxy method, but probably focuses on the limitations involved too much, without giving more information on the strengths. Two peer-reviewed articles I found in my own research are “Tree-rings, a key ecological indicator of environment and climate change” by Zhihua Zhang, and “Dendroclimatology: extracting climate from trees” by Paul R. Sheppard. Both articles have relevant and recent information, but are not in the Wikipedia article. Overall, to improve this article, I think the page could benefit from more recent sources of information, as most of the current sources are ten years or older. Also, I think the page could use more sources of information in general to have a more thorough and complete information base. Cjadamaitis (talk) 23:36, 22 February 2017 (UTC)
 * You are quite right. Please go ahead. Gabriel Kielland (talk) 08:10, 23 February 2017 (UTC)

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