Salzer et al 2009 – A First Look

Salzer, Hughes et al (PNAS 2009) is in the news. It reports that “unprecedented” high-altitude bristlecone growth, citing increased growth at Sheep Mountain, Mount Washington and Pearl Peak, but especially Sheep Mountain. pdf PNAS SI Salzer SI

CA readers are obviously familiar not just with bristlecones, but with Sheep Mountain. As pointed out in the MM articles, Sheep Mountain was the most important single series in the Mann PC1. Bristlecone chronologies had been introduced by Donald Graybill and arch-skeptic Sherwood Idso as supposed evidence of CO2 fertilization at high latitudes and IPCC 2AR in 1995 included a caveat.

Idso was startled, to say the least, when he learned, as a result of our work, that these chronologies were so influential in MBH.

Indeed, in retrospect, the primary “innovation” of MBH was probably their introduction of these HS-shaped series in temperature reconstructions.

As observed at CA on prior occasions, multiproxy authors quickly became addicted to bristlecone chronologies; the IPCC 2AR caveat was ignored and these chronologies were used in one multiproxy study after another.

Bristlecones were discussed at the NAS panel in 2006, who recommended that strip bark trees (especially bristlecones and foxtails) be “avoided” in temperature reconstructions. This recommendation was totally ignored by paleoclimatologists, who, if anything, actually increased their use of both strip bark chronologies and even Mann’s PC1 as a sort of solidarity against third party criticism. Subsequent to the NAS panel report, strip bark chronologies were applied in Hegerl et al 2006, Juckes et al 2007, Mann et al 2007, Mann et al 2008 and most recently in Tingley and Huybers (submitted).

We discussed bristlecones at considerable length in the MM articles, especially McIntyre and McKitrick 2005b (EE), neither of which is cited by Salzer et al, although the present interest in bristlecones surely owes something to do these articles.

We observed that there were a variety of issues surrounding whether bristlecone chronologies were unique antennae for world climate. In addition to being stressed by cold, Sheep Mountain bristlecones are in an extremely arid environment and subject to more than one stress.

These issues are not canvassed in Salzer et al; instead, they argue that the chronologies are correlated to modeled high-altitude temperature- something that will be discussed on another day.

Today, I want to discuss the chronologies themselves and more particularly the claim highlighted at RC that Salzer had shown that the Graybill-Idso wholebark-stripbark thing was merely a matter of inappropriate standardization.

CA readers are aware that Linah Ababneh’s 2007 Ph D thesis (Hughes was one of her supervisors) was placed online did a major update of the Sheep Mountain bristlecone data and did not replicate the Graybill HS chronology (opposite to Salzer’s result). Ababneh’s Sheep Mountain chronology, as shown in her PhD thesis and Ababneh (Quat Int 2007) did not have an anomalous 20th century. (Needless to say, it was not applied in Team multiproxy reconstructions. For example, Mann et al 2008 continued to use the Graybill chronologies from the 1980s.)

Ababneh’s work was discussed in a number of CA posts in fall 2007 – see for example here here Here is a plot comparing Ababneh’s Sheep Mountain chronology to Graybill’s:

At the AGU 2007 convention in December, I attended a presentation by Malcolm Hughes that, contrary to Ababneh’s results, reported unprecedented bristlecone growth – see the CA discussion here in a post entitled Malcolm Hughes and the Witness Protection Program. This presentation contained the main elements of Salzer et al 2009.

Despite Ababneh’s recent work on bristlecones, Ababneh’s name did not pass Hughes’ lips. Nor did Hughes make any effort to reconcile her results with the opposing results that he presented at AGU.

In my 2007 AGU report, I reported these bizarre events as follows:

Malcolm Hughes coauthor Matthew Salzer) made a presentation entitled “Twentieth Century Bristlecone Pine Tree Rings near Upper Tree Limit Wider than in Recent Millennia”. This included a report on Sheep Mountain. He showed a picture of Matthew Salzer on Sheep Mountain and praised his work. He said that there was no difference between strip bark and whole bark chronologies and showed a graphic up to 2005 with relatively wide recent ring widths. Linah Ababneh’s name did not pass his lips (the Ababneh thesis showing non-nomalous 20th results discussed here, here here), nor did he discuss her work. In Ryan Maue’s felicitous phrase, it was as though she had been put in witness protection. The words “CO2 fertilization” also did not pass his lips in a discussion of possible explanations for the recent behavior.

The situation is no better in Salzer et al. Ababneh is mentioned only in passing, and only as supposed authority in the SI for the assertion that “the divergence in modern period [between strip and whole bark] is clearly a result of the standardization technique used by Graybill and Idso (1)” – an assertion that (see below) is neither justified by the facts of the situation nor by Ababneh’s statements.

This failure to cite and reconcile opposite results is another instance of both shoddy practice by the scientists and all too typical indolent reviewing by senior journals. How could a competent reviewer of this article either be unaware of Ababneh’s contrary results or not require a reconciliation? Another frustrating aspect of this study is its failure to discuss seemingly discordant findings from Millar et al (2006) – findings which were noted in the NAS panel report (though IPCC refused to mention them.) Millar et al had observed subfossil stumps well above present treelines and reported:

Deadwood tree stems scattered above treeline on tephra-covered slopes of Whitewing Mtn (3051 m) and San Joaquin Ridge (3122 m) show evidence of being killed in an eruption from adjacent Glass Creek Vent, Inyo Craters. Using tree-ring methods, we dated deadwood to 815-1350 CE, and infer from death dates that the eruption occurred in late summer 1350 CE….Using contemporary distributions of the species, we modeled paleoclimate during the time of sympatry [the MWP] to be significantly warmer (+3.2 deg C annual minimum temperature) and slightly drier (-24 mm annual precipitation) than present.

On other occasions, I’ve expressed my view that reconciliation of regional results is something that should be of high priority if this field is to advance and it is disappointing that Salzer didn’t do so.

There are definitely some aspects of Salzer et al that deserve commendation. Like Ababneh, Salzer has updated the Graybill measurement data from the 1980s. Updating of proxies is something that has been urged here for some time but it would have been so much better if Salzer had discussed and reconciled to Ababneh.

Salzer’s article is virtually unprecedented in one respect: Salzer archived measurement data concurrent with publication – perhaps even responding in some measure to CA influence. Full marks to Salzer in this respect. I’ve downloaded the data and re-saved it at CA here .

Less satisfactory is the non-archiving of proper metadata. Information on the exact location of samples, altitudes, exposures and photos are important if one is to independently interpret the results of this sort of study. Pete Holzmann and I (particularly Pete) were able to provide this sort of documentation of our Almagre samples, complete with a detailed online photo inventory of individual trees. It is disappointing that Salzer did not take the opportunity to properly archive the metadata as well.

I’ll comment on several aspects of this paper, but I’ll comment in a little more detail today on one point that attracted attention over at RC, where they relied on a very strange analysis of strip versus whole bark as follows:

One final note: bristlecone pines often have an unusual growth form known as “strip bark morphology” in which annual growth layers are restricted to only parts of a tree’s circumference. Some studies have suggested that such trees be avoided for paleoclimatic purposes, a point repeated in a recent National Academy of Sciences report (Surface temperature reconstructions for the last 2,000 years. NRC, 2006). However Salzer et al’s study shows that there is no significant difference in their results when the data are divided into two classes—strip bark and non-strip-bark cases –when the raw unstandardized data are compared. So that particular issue has apparently had people barking up the wrong tree…

Once again, the folks at RC did not carry out even the most elementary due diligence on Salzer’s claims, which don’t hold up to the simplest scrutiny.

For the record, I’m not sold on claims that bristlecone growth pulses are due to CO2 fertilization as argued by Graybill and Idso. My comments below are directly only at Salzer’s incorrect claim that use of raw unstandardized data resolves anything.

First, here is the original graphic from Graybill and Idso, showing the difference between strip bark and whole bark chronologies at Sheep Mt.

Figure 2 showing Graybill and Idso 1993 Figure 5, Sheep Mt strip bark and whole bark chronologies

Salzer, to his credit, archived the original Graybill measurement data used in the comparison – a mere 16 years after publication. (Hopefully this will inspire Lonnie Thompson.)

Salzer emulated this figure in his Supplementary Figure 4B – which is an extremely muddy graphic, to say the least. I’ve done up a RCS chronology which in this case yields a virtually identical result to the original Graybill-Idso chronology and to the Salzer Figure, as shown below.

Figure 3. Sheep Mt Stripbark and Wholebark RCS Chronologies, using Graybill and Idso 1993 data (as archived by Salzer).

Salzer stated that the difference between strip and whole bark chronologies arose from standardization and that comparison “in an appropriate manner” “without artifacts introduced by standardization” leads to “very similar” results:

The apparent divergence of their strip- and whole-bark chronologies from the mid-19th century to the late-20th century is the result of the standardization scheme they used (Fig. S4B). When compared in an appropriate manner, without artifacts introduced by standardization, recent growth rates of strip-bark and whole-bark trees from the same environment are very similar. In light of these results, the suggestion that strip-bark pines should be avoided during analysis of the last 150 years (27) should be reevaluated.

As noted above, their Figure S4, shown below, is extraordinarily muddy. The chronologies shown in the lower panel are a dilated version of the graphic shown above. (I’ll show the corresponding ring width plot below.)

Salzer Figure S4, showing average width and chronology comparisons.

Here is a replot showing their Figure S4 in a non-muddy format. The change from a chronology plot to a plot of average widths is, in this case, a difference without a distinction. In the chronology plot, the difference between the strip bark and whole bark series manifests itself as divergence in the 20th century. In the ring width plot, the difference between the strip bark and whole bark series manifests itself as a divergence in earlier periods.

Figure 5. Re-plot of Graybill and Idso average width series.

Going from a standardized chronology to mean width has nothing to do with the price of eggs. The effect arises only from re-centering the series and not because of “inappropriate” standardization.

Interestingly, the differences between centering on the 20th century and centering on the pre-20th century period was discussed at CA here in connection with the difference between the Ababneh version and the Graybill version, where it was noted that if the two series were centered on the long period up to 1900, then there was a divergence in the 20th century; but if they were centered on the 20th century, the divergence was in the earlier period.

Doing the analysis using Graybill and Idso data simply squeezes the balloon, so that the divergence moves from one period to another. The authors have simply deluded themselves into thinking that they “explained” something and RC is too uncritical to notice.

For reference, I’ve posted up pdfs plotting ring width series by tree for all six sites plus the two Graybill-Idso series as and similar names, all shown for the 1500-2000 period only and all shown with a common y-scale.


  1. Posted Nov 17, 2009 at 10:36 AM | Permalink

    Layman Lurker

    Re: Layman Lurker (#86),

    Yes, I’d picked up that Ababneh wasn’t a co-author. She gets a mention in the SI I think.

  2. henry
    Posted Nov 17, 2009 at 11:08 AM | Permalink

    So did they go in and get new cores, or did they use the old Greybill data (IIRC getting close to 30 years old)?

    Steve: New cores.

  3. MrPete
    Posted Nov 17, 2009 at 1:35 PM | Permalink

    Where’s the discussion of how they selected the cores and series to be used? (Other than “treeline”)

  4. henry
    Posted Nov 17, 2009 at 3:01 PM | Permalink

    From the read me @

    The following data files are in support of the article: “Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes” by Matthew W. Salzer, Malcolm K. Hughes, Andrew G. Bunn, and Kurt F. Kipfmueller.

    The PRISM climate data can be found in the prism subdirectory. There are 4 instances of missing data from either PRL or MWA. In each case the missing month was set to previous month’s value. MWA: February 1937 Tmax = January 1937 Tmax; June 1947 Tmin = May 1947 Tmin. PRL: October 1924 Tmin = September 1924 Tmin; March 1952 Tmax = February 1952 Tmax.

    Ring width measurement files ending with the extension .rwl are text files in tree-ring decadal format as used at the International Tree-Ring Data Bank (ITRDB):

    The file shpage.rwl contains the ring-width data used to create the mean cambial age ring-width chronology in tree-ring decadal format.

    Ring-width data files from the three upper treeline bristlecone pine sites in decadal text format are: shp.rwl, mwa.rwl, and prl.rwl (Sheep Mtn., Mount Washington, and Pearl Peak respectively). These files contain newly developed ring-width measurements and some ring-width measurements from previously archived material. Series starting with the three letter designations SHP, MTW, and PRL were, at least in part, previously developed and archived at the ITRDB. Discrepancies between our series and previously archived series with the same ID represent additions to or changes to the originals based on quality control and new information provided through the use of the augmented data set.

    The ring-width data files used in the White Mountain elevational transect are shp.rwl, pal.rwl, cwl.rwl, and mwk.rwl (Sheep Mtn., Patriarch Lower, Cottonwood Lower, and Methuselah Walk respectively). The Methuselah series represents an update to previously archived material.

    The subsets of stripbark and wholebark ring-width series used for Sheep Mtn. and Cottonwood Lower are provided in the legend of Table S2 and can be found in shp.rwl and cwl.rwl. In both cases all the series were used from the most recent collections (SHP in 2005 and CWL in 2006) for which we had data on bark percent.

    The data files for the Graybill and Idso (1993) stripbark/wholebark comparisons (reference 13 in main paper) are shp_g_and_i_sbs.rwl – the ring-width measurements for the strip-bark trees, and shp_g_and_i_wbs.rwl – the ring-width measurements for the whole-bark trees.

    The eastern and western gridpoint density-based reconstructed temperature data are in the spreadsheet xd_eastwest.csv. See Rutherford et al. (2005) (reference 22 main paper) for more information about the density-based temperature reconstruction.

    Looks like they’re trying to “update the proxies”. Still no mention of the cores that Abeneh took, though.

    It might pay to go through their files and see if there are any files that have not been archived anywhere else.

  5. windansea
    Posted Nov 17, 2009 at 8:03 PM | Permalink

    Salzer et al’s study shows that there is no significant difference in their results when the data are divided into two classes—strip bark and non-strip-bark cases –when the raw unstandardized data are compared.</blockquote

    what the heck does this mean?

  6. Antonio San
    Posted Nov 17, 2009 at 8:54 PM | Permalink

    Looks like Ray Pierrehumbert is also a tree amigo expert…

  7. Rattus Norvegicus
    Posted Nov 17, 2009 at 9:31 PM | Permalink

    50 year smooth and different y-axis scale. Both seem to show a similar increase from about the mid 19th century onwards.

    • bender
      Posted Nov 17, 2009 at 9:40 PM | Permalink

      Re: Rattus Norvegicus (#104),
      I request your attention at unthreaded, please.

    • Dave Dardinger
      Posted Nov 17, 2009 at 10:49 PM | Permalink

      Re: Rattus Norvegicus (#104),

      50 year smooth and different y-axis scale. Both seem to show a similar increase from about the mid 19th century onwards.

      I’m guessing you’re responding to me, though you forgot to click the “reply and paste link”. I don’t buy your take on it. And why a 5 year moving average in the one figure and a 50 year moving average in the other? All that really does is make 4A look more like a continuing rise instead of a turn downward. Which, BTW, is not much help as you end up with a more or less constant rise from about 1830 on with some leveling off in the late 1900s. This is supposed to show AGW?? If this were legitimate I’d say it shows recovery from LIA.

  8. bender
    Posted Nov 17, 2009 at 9:31 PM | Permalink

    1. If the divergence in Fig 3A vs 3B (and in Fig 4A) is a function of “positive and negative responders” reponding differentially to temperature, then a nonlinear model is required to model temperature response. The high-elev grow faster; the low-elev grow slower.
    2. If the divergent response to precipitation in Fig 4C is also attributible to elevation differences, then precip cannot be ignored (and therefore neither can the temp*precip interaction).
    Conclusion: linear univariate reconstruction models are wholly inadequate.
    Based on these data, I actually don’t mind the idea of combining whole-bark and strip-bark samples. That is NOT the big issue. The big issue is where does the hockey stick blade go when you bother to account for precip and the nonlinear response to drought? Hypothesis: it disappears. PROVE ME WRONG.

  9. bender
    Posted Nov 17, 2009 at 9:36 PM | Permalink

    The differences between our relatively low-elevation and relatively high-elevation chronologies, and the similarity of distant treeline chronologies indicate the influence of temperature as a major factor in the modern high rate of growth at the upper treeline in Great Basin bristlecone pine

    Strawman. I never disputed temperature was a “major factor”. The question is quantitative: how much model specification error is there when you refuse to account for the OTHER major factor: moisture availability? Would this error tend to exaggerate a HS blade and diminish the MWP? You bet it would – if the MWP was drier than the CWP.
    Rattus? Dr. Pierrehumbert? Tom P? guru Bouldin?

    • bender
      Posted Nov 17, 2009 at 9:39 PM | Permalink

      Re: bender (#97),
      Please correct me if I am wrong. But as far as I can tell, this issue is dodged completely by these authors. Yet it’s been on the books for 3 years. Why the dodge? It’s the only question that matters!

  10. bender
    Posted Nov 17, 2009 at 10:01 PM | Permalink

    Salzer’s tricked you! The issue NEVER WAS strip-bark versus whole-bark. That was just NAS’s way of avoiding the much stickier issue of these inexplicable 6-sigma hyper-responseive trees. And Salzer is right: this is an issue that applies to ALL samples – as we have just seen in Yamal. Now, do not lie to me and tell me these wild excursions are the result of a linear response to temperature. Do not tell me you can compare these responses to ones that “could have occurred during the MWP but didn’t”. The MWP was drier. There’s a reason Ed Cook calls them “MWP megadroughts”. Read the blog.

  11. bender
    Posted Nov 17, 2009 at 10:01 PM | Permalink

    Drive-by Rattus.

  12. Rattus Norvegicus
    Posted Nov 17, 2009 at 10:06 PM | Permalink

    Actually, I think they did look at it and found that it was important at the relatively lower elevation sites, but not at the relatively higher elevation sites. All sites were pretty high at >2800m. At lower sites precip was strongly and positively correlated with growth and temperature was negatively correlated. So I don’t think they dodged it at all, it just didn’t seem to be significant at the upper sites demonstrating the strongest anomalous growth. SHP seemed to be the only upper site with any strong correlation to precip. You can see all this in Fig 3(c).

    • bender
      Posted Nov 17, 2009 at 11:13 PM | Permalink

      Re: Rattus Norvegicus (#99),
      Point to the line where they discuss the implications of the nonlinearity and interaction between temperature and moisture availability. Until you do that, my statement stands. Drive-by dodge artist.

    • hengav
      Posted Nov 18, 2009 at 10:07 PM | Permalink

      Re: Rattus Norvegicus (#28),

      I am trying to do some more reading. I have spent some time trying to find a 1979 paper by Paul Carrera entitled: The determination of snow avalanche frequency through tree-ring analysis and historical records at Ophir, Colorado

      Rattus, can you spare me a free copy?

      I found this gem for those of us who are “dim” on dendro from Jenkins and Herbertson which cites Carrera:'/using%20vegetative%20analysis%20to%20determine%20the%20extent%20and%20frequency%20of%20avalanches%20in%20little%20cottonwood%20canyon,%20utah.htm

      Avalanche impact can tilt or uproot trees causing them to produce reaction wood to retain upright growth. In conifers, the reaction wood is produced on the downhill side of the stem. The reaction wood differs from normal wood by its thick, dense cells and dark, reddish-brown color. Deciduous trees produce reaction wood on the uphill side of the tree. The cells are long, and dense with a grey or yellowish color. Reaction wood formation also causes eccentric ring growth resulting in wider than normal rings. Counting rings from the bark inward to the year of initial reaction wood formation provides a reliable date for the avalanche event.

      • bender
        Posted Nov 18, 2009 at 10:20 PM | Permalink

        Re: hengav (#98),
        I had been assuming all along that avalanche frequency in the spots where the trees are located was too low to be worth considering. But of course, we are talking 19th century when snow might have been much deeper.

  13. Rattus Norvegicus
    Posted Nov 17, 2009 at 10:18 PM | Permalink

    Nice work of goalpost moving bender. I see you moved them in another direction over at unthreaded.

    As far as the rest of your comment. It seems odd to me. It seems fairly clear that the upper treeline sites were sensitive to temperature and that the 20th increase in growth is real. If you aren’t happy with this conclusion, so be it.

    As far as drive-by? I’ve been patiently answering questions here and your direct question of me over at unthreaded. About as far from a drive-by as can be.

    However, your misplaced fury bores me. I’m leaving.

    • bender
      Posted Nov 17, 2009 at 11:04 PM | Permalink

      Re: Rattus Norvegicus (#113),
      I’ve been saying the same thing for 3 years. So no “goalpost moving”. Only in the echo chamber from which you shadow-box do things appear that way.

    • bender
      Posted Nov 17, 2009 at 11:05 PM | Permalink

      Re: Rattus Norvegicus (#113),

      misplaced fury

      More like: afraid to be tested by real questions.

    • bender
      Posted Nov 17, 2009 at 11:14 PM | Permalink

      Re: Rattus Norvegicus (#113),
      I responded to your unresponsive response. Please answer the question or admit that you are intentionally dodging it.

    • bender
      Posted Nov 18, 2009 at 12:14 AM | Permalink

      Re: Rattus Norvegicus (#29),

      As far as drive-by? I’ve been patiently answering questions here and your direct question of me over at unthreaded. About as far from a drive-by as can be.

      However, your misplaced fury bores me. I’m leaving.

      Yep. That’s a “drive-by”. Slag your opponent, fake a response, dodge the issue, pretend you’ve won an argument, and move on. From boredom. From lack of free time. Funny how you were entertained and had free time a couple of hours ago.
      Matthew Salzer does not address the issue of nonlinear responses to drought. Show me where I’m wrong. I LOVE to be corrected.

  14. Ian McLeod
    Posted Nov 17, 2009 at 11:32 PM | Permalink

    Quoting from Salzer et al:

    “The unprecedented growth observed in upper-treeline chronologies of the Great Basin over the last century is unmatched in millennia and is suggestive of dramatic environmental changes, most likely linked to increases in temperature.”

    Hmm, suggests, most likely, maybe, best explanation, sounds like a lot of wishful thinking to me rather than scientific evidence. That said, it’s a good paper, interesting, informative, and some good research done, but I have to say, their explanation for, or the causation of, the divergence problem, is surely incomplete.

    The divergence problem is due to a confluence of factors: CO2 fertilization combined with water-use efficiency (WUE), asymmetric growth habits, elevation, climate factors, and possibly something we haven’t yet considered, time will tell.

    Salzer et al suggestion that high elevation bristlecone pine data is a better temperature proxy because it is drier seems logical, but what about CO2? They seemed to have eliminated this as a factor because the tree-ring growth better matches the modern temperature profile than the theory of CO2 enrichment. Maybe they are right? But the rationalization will have to be better than their simple one dimensional explanation of correlation = causation before the likes of Graybill, Idso, LeMarche, Huang, Bender (heh, heh), me, and many others agree with them.

    Alas, this also means there will be a lot more hockey sticks published using bristlecone pine metadata coming soon.

    • bender
      Posted Nov 17, 2009 at 11:48 PM | Permalink

      Re: Ian McLeod (#35),

      dramatic environmental changes, most likely linked to increases in temperature

      Weasel words. Water is part of the “environment”. “Likelihood” – estimated how? “linked to” – weak. Drought is “linked to” temperature. But it does not equate to temperature. Semantic weaseldom.

  15. Steve McIntyre
    Posted Nov 17, 2009 at 11:32 PM | Permalink

    The following scripts produces the above figures.

    #data collated from




    #this gives reasonable replication of Graybill-Idso 1993 Figure and Salzer S4B

    chron.gstrip= RCS.chronology(gbill)
    chron.gwhole= RCS.chronology(gwhole)

    plot( chron.gstrip$series,xlim=c(1650,2000) ,ylab=”Chronology Index”,xlab=””)
    legend(“topleft”,fill=1:2,legend=c(“Strip”,”Whole”) )
    title(“Graybill-Idso as Chronologies”)

    #this compares to (dilated) to Salzer S4A

    x=ts( c(unlist( tapply(gbill$rw,gbill$year,mean,na.rm=T))),start=min(gbill$year))
    y=ts( c(unlist( tapply(gwhole$rw,gwhole$year,mean,na.rm=T))),start=min(gwhole$year))

    ts.plot(window(X,start=1650),col=1:2,ylab=”Ring Width”)
    title(“Graybill-Idso Ring Widths”)

  16. bender
    Posted Nov 17, 2009 at 11:41 PM | Permalink

    Ok, Rattus. Still bored? Let’s go, friend.

  17. bender
    Posted Nov 17, 2009 at 11:44 PM | Permalink

    Prove to me that the higher elevation sites aren’t the wettest in a millllyun years. A few tens of metres can make a huge difference at those elevations. (And PRISM ain’t THAT good.)

  18. Steve McIntyre
    Posted Nov 17, 2009 at 11:48 PM | Permalink

    For reference, I’ve posted up pdfs plotting ring width series by tree for all six sites plus the two Graybill-IDso series as and similar names, all shown for the 1500-2000 period only and all shown with a common y-scale.

    • MrPete
      Posted Nov 18, 2009 at 12:25 AM | Permalink

      Re: Steve McIntyre (#39),
      You want intra-tree variability?

      Check out the multi-core sample sets such as 958 (p25), 51 (p57), 610 (p68), 68 (p72), 890 (p78). Ring widths vary as much as several hundred percent over long periods of time.

      How does this impact the CI of the analysis?

  19. Ian McLeod
    Posted Nov 18, 2009 at 12:08 AM | Permalink

    Yep, weasel words is a less diplomatic way of saying it, but yes, they are weaselly.

  20. bender
    Posted Nov 18, 2009 at 12:16 AM | Permalink

    Here is a replot showing their Figure S4 in a non-muddy format.

    When are we going to get away from subjective graphical comparisons and move on to robust statistical tests of population homogeneity? These graphical eyeball tests suck.

  21. Posted Nov 18, 2009 at 12:48 AM | Permalink

    In my perception, that some old trees 150 m within the tree-line and not below started growing fast in the last century is a very interesting fact deserving attention. It is the persistent, not to say maniacal, intention to link it — by any means — to warming that appears absolutely unscientific. Fashion rules the mainstream journals; if you do not link your study to AGW, the limited space will be taken by others who do. How many studies that did not confirm warming remain unpublished and their authors, by consequence, discouraged from continuing their careers in science? Is there any statistics?

    I can testify that the pattern is wide-spread by my own experience. Once we made a study linking largest body size in extant air-breathing cold-blooded animals to ambient temperature from consideration of their energy budget, to show that the largest animals live in the warmer regions. We submitted our work (no whatsoever link to climate change) to Nature and it was rejected even without being sent out to review, just of no interest. Four years after our work was published in a different journal, a group of paleobiologists took up our approach to reconstruct paleotemperatures from the body size of the largest extinct snake they had excavated. This research was published in Nature, received a News and Views coverage, and an extensive discussion. In comparison, the largest extinct frog study published a year earlier did not make it to either Nature or Science (to be accurate, I do not know whether the authors had submitted it there). But interestingly, the frog, unlike the snake, did not reconstruct paleotemperatures.

    Yielding to fashion, the mainstream scientific mass-media are sweeping unprejudiced science away to make space for loud speculations. In the extreme, even if an author has serious results at hand, he will be unable to publish them high unless making a clown of himself by stretching his conclusions to say at least something about climate change. With each new generation of researchers the proportion of clowns favored by such artificial selection can be expected to hockey-stick. Talk AGW or die.

    • Kenneth Fritsch
      Posted Nov 18, 2009 at 10:25 AM | Permalink

      Re: Anastassia Makarieva (#45),

      Thanks for those insightful observations from real life – that are a major reason I participate here.

      • Dave Dardinger
        Posted Nov 18, 2009 at 10:37 AM | Permalink

        Re: Kenneth Fritsch (#72),

        that are a major reason I participate here.

        That and the fact that there are people here to help you with your grammar. (Note: if you left out the ” – ” your sentence would just be awkward rather than grammatically wrong.)

  22. Jim Steele
    Posted Nov 18, 2009 at 12:50 AM | Permalink

    I am having major trouble with the assumption that their data above the transition elevation illustrates temperature dependence, thus is a more reliable climate proxy. They concluded,

    Above the transition elevation, ring width is strongly positively associated with temperature and also is weakly positively associated with precipitation. Below the transition elevation, ring width is strongly negatively associated with temperature and also is strongly positively associated with precipitation.”

    First, they notably did not say there was a “significant correlation” with temperature. Therefore there was most likely substantial variability in ring widths suggesting other factors are at play. And they mention a lag effect. They later massaged the lack of observed temperature significance by stating there was a significant correlation with “temperature proxy data”.

    But most troubling is the “strong negative correlation with temperature below the transition elevation”. They claim the ring width is governed by sink variables meaning biosynthesis of the wood. Increased temperatures typically increase most metabolic responses because increased temperatures increase enzymatic rates. Increasing temperatures typically do not cause decreased metabolic activity until temperatures reach a level that disrupts the enzymes tertiary structure. It is highly unlikely that within the small observed temperature ranges observed above and below the transition elevations that such drastic differences would be observed causing negative or positive growth. And since below the transition elevation we would observe slightly warmer temperatures and negative growth trends, why would we expect the slight warming of higher elevations to then cause positive growth?

    The idea that at tree line there is a temperature threshold makes perfect sense, and it is likely that at that at a threshold temperature a greater proportion or ring width variability would be accounted for by temperature. But if temperature is such a critical and sensitive variable, one would not expect negative correlations at slightly lower elevations where temperatures are above the threshold. We would expect only a smaller proportion of the ring width variability to be accounted for by temperature as other factors like precipitation exert greater influence. The observed negative correlation with temperature just does not make any sense within the small range of temperatures differences between those elevations. But it seems like they want to have their cake and eat it too.

    • Craig Loehle
      Posted Nov 18, 2009 at 8:04 AM | Permalink

      Re: Jim Steele (#46), The elevation threshold is a red flag that something weird is going on. It is not a proof of global warming. It is handwaving for not understanding the system. Payette would be able to explain such a thing much better.

      • bender
        Posted Nov 18, 2009 at 8:50 AM | Permalink

        Re: Craig Loehle (#52),
        Re: Jim Steele (#46),
        The nonlinear model of positive and negative responders (responding to drought, not temp, not precip) is intended to answer this question.
        What’s the role of cloud condensation in making the top of the alpine treeline slightly wetter than just 100m downslope? Are these dry environments shifting to a more “cloud forest” condition? What would Lindzen say about the possibility of cloud formation at high elevations in response to CO2 forcing?
        There is no way in hell these six-sigma excursions are a linear response to temperature. Give it up, young dendros. You’re tarring yourselves with Hughes’ ideological malpractice.

      • Jim Steele
        Posted Nov 18, 2009 at 9:59 AM | Permalink

        Re: Craig Loehle (#52),

        I am not sure what you are trying to tell me. I was simply arguing that the different responses of tree growth above and below the transition elevation strongly suggest that temperature is NOT the variable causing the different ring widths.

  23. Kruddler
    Posted Nov 18, 2009 at 3:17 AM | Permalink

    “How could a competent reviewer of this article either be unaware of Ababneh’s contrary results or not require a reconciliation?”

    This issue of the general review process, particularly for certain journals such as PNAS, is all too familiar. I know of a number of less than adequate papers in the field of biological sciences that have made their way past peer review via tactics such as the “choose-your-own-reviewer” method. This results in a raft of shoddy papers and makes a mockery of the concept of peer-review.

  24. Posted Nov 18, 2009 at 4:31 AM | Permalink

    I’ve invented a new word for this phenomenon: Pinusaristataphilia – the unreasoning wish by some non-statisticians to use bristlecone pines as proxies well after everyone realises their growth has nothing to do with world climate.

  25. Geoff Sherrington
    Posted Nov 18, 2009 at 5:54 AM | Permalink

    From Google Earth, Sheep Mountain Calif (if this is the correct Sheep Mountain, about 36.3 x 118.5 deg)sits in a rather barren rough circle of 500-1000 m diam which marks an elevation drop of 150 m. There are a few trees on this plateau and I guess they are the ones that show the unprecedentedness.

    It would be interesting to examine a concept used elswhere, where artificial aerial fertilisation of undulating ground is done by dropping along the ridges. Precipitation takes the fertilizer to lower levels and if there was enough applied, the whole area is enhanced. If only a little is applied, then the top of the ridge has first bite.

    I’m not familiar with precipitation patterns here and I do not know if the description is relevant. But, I could imagine nutrients like sulphate from SO2 getting caught in the snow on that plateau and giving these trees the first bite of the cherry. Industrial SO2 in air from industry more or less fits the time scale. Explanation fails if precipitation like snow goes down the slopes for miles – except that high-altitude growth seems to be limited to a couple of summer months, so the highest points have the longest availability of extra nutrient.

    But why bother pulling another tooth when dentures are needed?

  26. KevinUK
    Posted Nov 18, 2009 at 7:54 AM | Permalink

    OK, I think this is a god sign of desperation on the part of the Team.

    Now that Keith Briffa’s ‘hockey stick creating’ CRU 12 is looking decidedly dodgy, it’s appears that the Team have now decided to resurrect the ‘bristlecones’ – how else are the goingto create hockey sticks otherwise?. Looks like they’ve ‘moved on’ again and have decided to start ‘chasing the dragon’ (use heroin) again now that their supply of cocaine has been impounded.

    Don’t you just love they way they’ve moved the goal posts again with this strip bark v whole bark Figure 5 above? It’s a good job Steve M is on the case continuing to keep an eye on ‘when the pea is moved under the thumble’.


  27. Craig Loehle
    Posted Nov 18, 2009 at 8:08 AM | Permalink

    PNAS is a country club. An outsider may get a standard review. But if your good buddy is a member and you send the ms to them, you can get very favorable treatment. Who was the editor for this one?

  28. henry
    Posted Nov 18, 2009 at 8:24 AM | Permalink

    For them to move to an elevation threshold assumes that the threshold hasn’t changed over time. Other studies they’ve used had implied (IIRC) that the increase in temps caused a movement in the treelines.

    • Posted Nov 18, 2009 at 9:03 AM | Permalink

      Re: henry (#54),

      What henry said.

      What are the relative time scales for changes in the ‘transition elevation’ and the life-time of the trees? Could not a tree be both above and below the transition elevation in its lifetime and still survive?

      Plus, exactly how ‘thick’ is this transition elevation? Isn’t it more likely that there is a continuum in the response to limiting factors as a function of elevation?

      • bender
        Posted Nov 18, 2009 at 9:11 AM | Permalink

        Re: Dan Hughes (#58),

        Isn’t it more likely that there is a continuum in the response to limiting factors as a function of elevation?

        Sure. And if you were to smaple enough trees you could probably show that. I don’t see where the authors are denying this possibility.

    • bender
      Posted Nov 18, 2009 at 9:15 AM | Permalink

      Re: henry (#54),
      Assuming a fixed threshold is obviously an approximation. (They should mention this as a point in the discussion.) Allowing for a variable threshold (shifting treeline) might make a difference for modern-medieval comparisons, but wouldn’t change the material results.

  29. Steve McIntyre
    Posted Nov 18, 2009 at 8:55 AM | Permalink

    A couple of further points. We’ve discussed upside down U-shaped responses of ring width to temperature. Given the tight sensitivity to elevation, to carry out a proper statistical analysis, one needs to record the elevation and exposure of every tree and record the meta data. This isn’t hard to do. We did this at Almagre as an example.

    As one goes a couple of hundred meters down-gradient, ring widths respond negatively to temperature; as one goes a couple of hundred meters up-gradient, ring widths also respond negatively to temperature (indeed, there aren’t any trees.) This surely raises the U-shaped reconstruction problem.

    A question here – it is my understanding that bristlecones survive in situations where they can’t reproduce. This would affect the gradient in a complicated way.

    There is definite evidence of warming at these sites. Trees are germinating at higher elevations.

    • bender
      Posted Nov 18, 2009 at 9:05 AM | Permalink

      Re: Steve McIntyre (#56),

      A question here – it is my understanding that bristlecones survive in situations where they can’t reproduce. This would affect the gradient in a complicated way.

      That’s a good point. It is an effect noted in many treeline studies. But I don’t recall anybody commenting on the implications of zero reproduction for enhanced growth. Over long time scales, when climate is warming, the two are correlated (higher growth comes first, then reproduction, then treeline advance). Over short spatial scales, however, this correlation could break down. Non-reproducing trees could grow faster than nearby trees that are reproducing.
      Maybe the trees with monstrous six-sigma excursions are not yet reproducing? Do dendros record the presence/absence of cones as metadata?

  30. bernie
    Posted Nov 18, 2009 at 9:00 AM | Permalink

    Congratulations on helping to get the professionals to do what they should already have been doing: archive their data.
    It is astounding how many serious issues have been raised with this paper – even before the data itself as been systematically scrutunized (see MrPete (#44)). I also found Jim Steele’s clear articulation of tree growth factors very helpful. If the findings of an apparent reversal of the temperature correlation with elevation (and precipitation) is correct, then the size of bender’s iteraction of temperature and precipitation would have to be very large, would it not?
    This should prove to be a very rich discussion.

    • bender
      Posted Nov 18, 2009 at 9:09 AM | Permalink

      Re: bernie (#57),
      I think the interaction term could be very large. I can not speculate as to why they would not explicitly test for that possibility. If I were a reviewer I would have insisted on that. Perhaps they would have whined about the low of degrees of freedom. C’mon guys, it’s the 21st century! Do you really need to troll for correlations month by month? What a waste of degrees of freedom.

  31. Posted Nov 18, 2009 at 9:15 AM | Permalink

    In this paper the differential response to release (e.g., elimination of competing trees) of slow versus fast growing trees is quantified as a species-specific exponential curve.

    Black and Abrams, 2004, Dendrochronologia 2002, 31-42:

    Identifying releases from suppression represents one of the most fundamental dendroecological procedures for quantifying forest disturbance histories.

    In general, a release is defined as an event when the percent-growth change in a tree-ring series exceeds a given minimum threshold, such as 25%, 50%, or 100%, which in some criteria must be maintained for a certain length of time such as 5 or 10 years.

    field experiments have demonstrated that slow-growing trees have greater release potential than fast-growing trees, as do young, small-diameter trees compared to old, large-diameter trees.

    Substantial logging events occurred in Bear Meadows in the 1880s… Detailed dendroecological studies have been conducted in Bear Meadows and Schall’s Gap, and reveal that massive disturbances initiated synchronous releases, which was immediately followed by a major pulse in regeneration.

    Here is a figure from Black and Abrams 2004 showing the reaction of trees to release, per cent change versus 10-years radial growth (as I understand, it should relate to ten times the mean ring width). As one can see, the slowest-growing trees display the highest response.

    A check for historical ecosystem disturbances like both logging and grazing (destroying the young undergrowth and lessening the resource competition for the older trees) should be a prerequisite for any climate reconstruction based on living organisms. As I understand, the problem is not mentioned by Salzer et al.

    • bender
      Posted Nov 18, 2009 at 9:30 AM | Permalink

      Re: Anastassia Makarieva (#63),

      slow-growing trees have greater release potential

      You know what I’m wondering about Anastassia? Nitrogen buildup while the old tree is sleeping. When it wakes up, is it sitting in a happy pool of fertilizer? Root systems fully extended, ready to soak it all up in one gulp?

    • bender
      Posted Nov 18, 2009 at 9:34 AM | Permalink

      Re: Anastassia Makarieva (#63),

      the problem is not mentioned by Salzer et al

      These bristlecone pines are probably not that engrossed in intraspecific competition (between trees of the same species). So I’m not concerned about those kinds of release events = “disturbances” that might be associated with a change in tree density. I assume that’s why they don’t bother discussing it. It’s the other stuff that concerns me.

      • Posted Nov 18, 2009 at 10:18 AM | Permalink

        Re: bender (#65), Why do you think

        bristlecone pines are probably not that engrossed in intraspecific competition

        I remember you also rejected that for Yamal.

        The fact that the tree-line is open canopy does not prove the trees do not compete. Their root systems can compete severely, especially when growth conditions are tough. I observed many trees growing on bare rocks where every slightest rift is rivaled by roots of several trees, while stems themselves are placed wide apart.

        If, e.g., sheep grazed on that Sheep Mountain a hundred years ago and removed all understory apparently the competition became less intense for those trees who remained.

    • Craig Loehle
      Posted Nov 18, 2009 at 9:51 AM | Permalink

      Re: Anastassia Makarieva (#63), In the figure you post, we see 800% growth increases in the most suppressed trees once released from competition. Hemlock can survive extreme growth suppression. I am familiar with the work of Mark Abrams (2nd author) and he is very good.

      • terrence
        Posted Nov 22, 2009 at 1:42 PM | Permalink

        Re: “I am familiar with the work of Mark Abrams (2nd author) and he is very good.”,

        Dear Dr. Loehle,

        you are often portrayed as the reasoned and logical scientist here. however, if you think Marc Abrams is “very good”, it indicates that perhaps 1) you do not know what good science is or, more importantly, 2) understand dendrochronology. You need to increase your familiarity with the subject.

  32. bender
    Posted Nov 18, 2009 at 9:41 AM | Permalink

    A bit more water, some nitrogen, a tiny increase in temperature. Ask lucia what this does for her garden in chilly Chicago. Six-sigma synergy? Well, maybe only three. But at treeline? Maybe a six-sigma synergistic surge is not unreasonable.

  33. BKC
    Posted Nov 18, 2009 at 10:04 AM | Permalink

    Re: <a href=”javascript:edInsertContent(edCanvas,’Re:%20John A(#49)

    “Pinusaristataphilia” – The colloquial expression for this is pinus envy.

  34. Wolfgang Flamme
    Posted Nov 18, 2009 at 10:38 AM | Permalink

    My wife knew it long before: Skin peeling is a fountain of youth.

  35. harold
    Posted Nov 18, 2009 at 11:08 AM | Permalink

    Pretty views and some amazing trees in this short feature by the National Science Foundation. With comments by Hughes and Salzer.
    “Written in Tree Rings”

    • Posted Nov 18, 2009 at 11:51 AM | Permalink

      Re: harold (#75), Very informative indeed. The place looks like an ecological disaster happened there, especially as revealed by this frame from the movie. I can be mistaken as an alien ecosystem is like a foreign language, but the road is strongly suggestive of commercial use a few decades ago, lack of coherent grass cover suggests fires. Medium aged trees conforming to commercial standards were removed, old crooked non-standard trees were the ones that remained. It is unbelievable not to look into disturbance history in a place looking like that.

      • Craig Loehle
        Posted Nov 18, 2009 at 1:37 PM | Permalink

        Re: Anastassia Makarieva (#76), In the 1940s through 1960s it was common in studies in ecology to document the past land use history of study sites, because it was still evident. After that, people began to ignore past land use or disturbance history, and made the mistake of treating many second growth forests as if they were native, even those growing on abandoned agricultural land. This error was quite serious in the Amazon, where everyone “knew” no agriculture was practiced, though it now seems they were mistaken about this. Thus IF these mountains were affected by sheep grazing (which is not impossible) or by fire (more difficult due to little ground cover) the past history needs to be explored, but was probably overlooked.

  36. bernie
    Posted Nov 18, 2009 at 12:35 PM | Permalink

    Are there earlier pictures or records of what happened in these areas? If Anastassia is correct, might even satellite images be around? Many of the shots look like they are from the moon rather than the earth. Clear cutting should surely have left more stumps, etc.? But then parts of upstate New York that were clear cut in the early 19th Century have not recovered and no longer have any soil.

    • Posted Nov 18, 2009 at 1:09 PM | Permalink

      Re: bernie (#77), If we look at Fig. 4A and B in Salzer et al., one can clearly see that the growth spurt began in the first half of the 19th century. If a massive clear-cut (or intense selective cutting) dated back to that time, few stumps would remain in almost 200 years since then, especially if there were recurrent fires in the area. One should check local historical record.

      Also, if in the result of logging the uppermost trees were destroyed, the immediately adjacent inhabitants of the new (lower) tree-line could benefit (fertilized) by the nutrients driven downslope from the abandoned (and, perhaps, subsequently burnt) eroding area by the water flow. Because trees can only prevent soil erosion — keeping soil nutrients for themselves — while alive. This view suggests to me that perhaps there used to be many more trees upside the hill a couple of centuries ago.

      • MrPete
        Posted Nov 18, 2009 at 1:44 PM | Permalink

        Re: Anastassia Makarieva (#78),
        If true, then yes they have found evidence of anthropogenic influence on proxy growth… just not quite the source they’re suggesting.

        Seems there ought to be logging records, old photos, etc etc that could provide evidence one way or another. That road must have been there for a long time. Note that there’s a road high up in the distance in the second photo as well.

  37. bernie
    Posted Nov 18, 2009 at 2:17 PM | Permalink

    If I have the location correct, the trees are in and around the Inyo National Forest. Perhaps a reader from Eastern California can chime in, but apparently Inyo was involved in mining in the 19C. There are some early photographs at the Eastern California Museum . They all suggest that the landscape was pretty much the same as it is now.

  38. Posted Nov 18, 2009 at 2:34 PM | Permalink

    What Mann did originally was perhaps to notice that bristlecone pines gave the required recent upswing if you include only the last 1000 years but the data was too noisy to look like a perfect hockey stick so he had to include a bunch of other proxies to smooth the early record out. That didn’t work since it killed the blade of the stick, so instead of publishing a negative result he “accidentally” ran the averaging math for only the recent century instead of the full ten centuries so to reject proxies that showed no hockey stick blade at all yet still acted to smooth the handle greatly. Having been discovered finally for having done this, the community of alarmists then switched to in-your-fact cherry picking. Mann made a new hockey stick that used an algorithm to bluntly cherry pick proxies series by automatically rejecting those that didn’t match the warming of the latest century. That’s not bad science. It’s just bad logic. And it makes the work extremely speculative since random noisy data give the exact same output of a hockey stick. In this case there is no obvious cherry picking because the entire study itself is one big cherry pick. This is the sort of science that should have been put forward from the very start. I doubt that a simple “audit” is going to skewer it because a driver other than temperature would be needed, or a driver of local temperature other than CO2 discovered, or finally to show that recent warming is local and anomalous rather than global. Only that later might be subject to an auditing process.

    One thing I’d like to know is if the specific regions they used were cherry picked. Are there lots of other bristlecone populations that fail to show this growth spurt along the tree line?

    I’d also like to see not just 1950-present magnified (figure 2b) but a few centuries to make the crucial judgment as to whether tree ring growth spurts really do only occur in abundance during and not before the mild rise of CO2 from 1900 and the steep rise mid-century. Is this yet another case of a growth spurt that started in earnest before the CO2 uptrend did? And did it mellow out during postwar cooling?

    It would be nice to see the graph of lower-treeline trees since they are said to be a negative proxy of temperature. Do they also show a hockey stick blade? You would think if they did that the authors would rather enjoy including it.

    The problem with this study doesn’t seem to be the paper itself but in how it is interpreted. It’s little surprise that the proxy that gets cherry picked in order to make hockey sticks appear in multi-proxy studies itself shows a hockey stick! That’s really all this paper does is to confirm that fact. But in the original hockey stick was shown to be based on “incorrect” statistics, nobody in the AGW community started shouting that if one thew out all other proxies and only used bristlecones that it made the issue not matter. Yet now that is exactly what they are doing. Caught red handed trying to over-include an early version of this study into the mix they now unmix it and wave it around as their new banner as if that clears their early work up and justifies it.

  39. Dave Dardinger
    Posted Nov 18, 2009 at 2:44 PM | Permalink

    Somehow this whole “whole bark vs strip bark” doesn’t matter attempt reminds me of the various attempts to justify not allowing for UHI in temperature records. It’s clear that they do matter, but it’s so much easier to find an excuse not to have to worry about them.

  40. Micky C
    Posted Nov 18, 2009 at 2:58 PM | Permalink

    Something that fell out of the paper when I was reading it, and something that Lucia showed in her Cherry Picking thread (and subsequent Rocky-like II and III returns) was when they compared ring density proxies to the ring width data. From the cherry picking thread it seemed apparent (as it is mathematically consistent) that if you try and take a sub sample of a time series data set of red noise, autocorrelated data or a straight forward periodic function, where each set has zero mean over the time interval then you can select upticks if the function has an uptick in the subset interval that you select.
    Now if you can include other parameter sets from the same trees, like ring density then you can maybe screen the proxies better so that upticks become more probable across a range of tree characteristics. So I was surprised they hadn’t included ring density for the same trees that they used for the ring widths to see how this compared with the other ring densities and maybe tried to get ring widths for these trees. It’s a bit apples against oranges rather than here’s my apples and oranges together against another apples and oranges together set.
    As for the reconsidering of the strip bark, I think the photo’s on Steve’s last post are self-explanatory as to why you would want to avoid such a tree.

  41. EdeF
    Posted Nov 18, 2009 at 3:22 PM | Permalink

    Some background—The White Mountains have had human contact for
    thousands of years, up until the 1850s the main contact was from the
    local Shoshone Indian tribes that still live in the area. They would
    migrate up into the mountains (both Sierras to the west and Whites
    to the east) in the summer to gather pine nuts. Since the time of
    European settlers, ranchers and miners circa 1850s onwards there has
    been some interaction in the White Mtns. Basque sheephearders have
    been in the Eastern California and Nevada over the last 150 yrs,
    displacing the native Bighorn Sheep. Extensive mining has gone on in the mountains and deserts of Eastern California also at different times. (Might want to ask some Canadian gold miners what they think of opening up some abandoned mines now that the price of gold has gone up.) Wood was used in the old times to help run steam railroad engines in the days when a RR ran from Los Angeles to Owens Lake. Old charcoal kilns are still around from the days when charcoal was made in Beehive kilns to be used in mining operations. In 1846-47 there was a massive snowstorm in the west that left drifts up to 10 feet in this area. Someone might want to look at old records of avalanches in this area about April 1847. The same thing happened in March 1969. I would suspect downslope trees might have been affected after these huge snowfalls. The University of California has a high altitude research center in the White Mtns called the Barcroft Lab with several stations and observatories. I think it is very unusual to have a continuous weather station right next door to one of the key tree areas that are of interest. Access to the BCPs is limited today since they are in a protected area. Finally, a few weeks ago they experience 168 mph winds in the area. Image what type of havoc this magnitude wind has on trees when gravel and dust bits are being carried along in it. You’re not
    exactly sitting at the beach in San Diego.

  42. Wolfgang Flamme
    Posted Nov 18, 2009 at 3:26 PM | Permalink

    Looking at this discussion I’ve probably been missing something.

    I understand that a ‘normal’ tree in a ‘normal’ climate will follow some ‘normal’ characteristic path of development through allometric space (one dimension of this characteristic path is reconstructed by RCS). However when a tree becomes severely damaged (strip-barked), some of these allometric proportions are changed. Eg when a whole tree looses half of its living biomass this way, it is not transformed back to a much more juvenile, nevertheless characteristic state of development but instead leaves the path of normal development. Thereafter, it will most likely follow a one-of-a-kind development. Yes, there might be commonalities within damaged trees such as a tendency for late growth spurt under favourable conditions. But we still wouldn’t directly compare strip-bark trees with whole trees given the very different circumstances, would we?

    Nevertheless, that’s what is in the Salzer paper. Arguments here are about the influence of undocumented logging, for example. So what am I missing?

  43. Tom C
    Posted Nov 18, 2009 at 5:44 PM | Permalink

    From the post:

    We observed that there were a variety of issues surrounding whether bristlecone chronologies were unique antennae for world climate.

    Steve always admonishes us to “watch the pea under the thimble”. Likewise, we have to always keep the big picture of these studies in mind. Even if all the protocols and stats are correct in these proxies (which I don’t believe for a minute), you are still left with only 2 proxies from very small geographic regions that show the 20th century uptick.

    So, there is a big contradiction at the heart of these analyses, which is that absent some proven, mechanistic connection to global MT, these regional effects can at best be weighted in some way and averaged against all the other regional proxies. Any other approach is a fishing expedition for spurious correlation.

    OT, I know, but in the midst of the excruciating detail of deconstructing these studies it’s important to not let the Team get away with this larger fallacy.

  44. FHSIV
    Posted Nov 18, 2009 at 9:15 PM | Permalink

    Here are some anecdotal notes based on my personal experience in the Sheep Mtn. area. I hope this can provide some information that is useful to this discussion.

    I spent a summer in the 1980’s as a geology student living at the UC research station facilities located at Crooked Creek approximately three miles from the summmit of Sheep Mtn. My field study area was nearly centered on Sheep Mountain and included the locations of three of the four tree populations from this area used in the Salzer study (except for Methuselah which is a few miles south and at a lower elevation).

    It is interesting to note that the distibution of the bristlecones in the area is strongly dependent on bedrock lithology. The trees have a definite affinity for sites underlain by calcareous meta-sedimentary bedrock (Deep Spring Fm. limestones and Reed Fm. dolomites) compared to an almost complete absence from areas underlain by silicic meta-sedimentary bedrock (Campito Fm. quartzites). In some places, the location of a geologic contact could be accuratley mapped from a far on the basis of the extent of the trees. On these slopes, the soils are thin, discontinuous or non-existent with most of the surface area consisting of outcropping bedrock. Reed Dolomite is almost pure white (literally almost as white as snow, take a look at Google Earth) while the quartzites are dark brown with a surface veneer of black oxides. As a result, the maximum temperatures developed on soil/bedrock surfaces exposed to the sun differ significantly between areas underlain by the different rock types. I would imagine that this difference has some effect on the seasonal duration and distribution of near surface soil mositure content. The story I remember from the botany students was that the tree distribution was governed by germination that was favored by longer durations of relativley higher soil moisture content on the limestones and dolomites. I suppose that this could also effect growth rates during the life of the trees?

    A couple other possibly relevant items. First, in the White Mtns., the proportion of the total annual precipitation that occurs as winter frontal-type precipitation varies annually with respect to the amount of monsoonal-type summer season precipitation. Being in the rain shadow of the Sierra Nevada, and losing most of the snow that does fall to sublimation, I would think that an increase in summer convectional precipitation might have a significant impact on tree growth?

    With regard to sheep, the desolate look of the gently sloping alluviated valleys along the crest of the range is attributed to extensive sheep grazing in the late 19th century. I don’t know how long this lasted, but you can still find the low, square, stone structures that the Basque sheepherders lived in while tending their flocks the northern and eastern slopes of Sheep Mtn.

    Lastly, deforestation of portions of nearby mountain ranges (Inyo, Panamint, Argus, etc.) due to cutting of trees to make charcoal for roasting metallic ores and for shoring underground workings was widespread in the late 19th Century. However, this mostly involved pinyons and junipers at lower elvations near known historic mining districts (especially where smelting was performed). The area surrounding Sheep Mtn. is shot full of all kinds of adits and small shafts, but there were no mines in the immediate vicinity that I recall that had significant production. That said, wood cutting for charcoal production sometimes did involve freighting long distances to the kilns. However, there is a lot of easier wood on the lower slopes of the range.

    Now that I think about it, the largest mine in the vicinty was the Eva Belle which is relatively close to both the Cottonwood and Patriarch sample locations. Similarly, the Mexican Mine has a good sized tailings pile and is right next to the Methuselah site.

    I hope this info was interesting for some of you! I sure enjoyed recalling it!

    • Steve McIntyre
      Posted Nov 18, 2009 at 9:32 PM | Permalink

      Re: FHSIV (#91),

      Have you read McIntyre and McKitrick 2005 (EE)? We discuss these extremely interesting issues overlooked by dendros.

      We noted that bristlecones and large sagebrush demarcated geological strata, including an illustration from an old picture.

      We discussed the known phenomenon of growth release for trees following 19th century overgrazing by sheep:

      There is a published reference to the introduction of large commercial sheep flocks in the late 19th century in the White Mountains CA [St. Andre et al. 1967], where the key sites of Sheep Mountain and Campito Mountain are located. The founder of the Sierra Club, John Muir, complained of the depredations of sheep in the Sierra Nevadas (adjacent to the White Mountains) as “hoofed locusts” [Muir, 1911]. Carl Purpus, a late 19th century botanical collector in the Sierra Nevadas, stated in 1896 that commercial flocks had cleaned out all grass to the top of Old Mt Whitney [present-day Mount Langley, which reaches 4,280 m] [Ertter, 1988]. Allen (pers. comm., 2004) said that there was a large commercial sheep trail at Jicarita Peak NM, another bristlecone pine site studied by LaMarche and Stockton [1974]. In severe high-altitude terrain, even after the departure of commercial flocks, a small population of bighorn sheep could prevent the re-establishment of grass (Leslie Thomas, Colorado Springs, landscape architect, pers. comm.) Since grass (and other herbs) compete with pines for scarce moisture, one can hardly exclude, on a priori basis, the possibility of a connection between anomalous 20th century growth rates of bristlecone pines and a growth release following 19th century overgrazing, as experienced elsewhere in the American Southwest.

      In early days of CA, I did some posts on mining towns. Some of the roads that Graybill used to get to the bristlecones were developed for long-closed 19th century mines. mentions the Cerro Gordo mine in the area under discussion. I had material for other posts of this type for other bristlecone sites, but didn’t get around to doing them.

    • bernie
      Posted Nov 18, 2009 at 9:36 PM | Permalink

      Re: FHSIV (#91), Very helpful. Excellent recall of the specifics. Are there references that provide additional history and descriptive information?

    • Geoff Sherrington
      Posted Nov 18, 2009 at 11:33 PM | Permalink

      Re: FHSIV (#91),

      My apologies, I did not read your post on geology before my speculation in 103. It is easy to get pat way through the new day’s offerings, respond, then move on (sorry, “advance”) to later posts that deal with the same subject, especially from the other side of the world when many posts can accumulate overnight.

  45. Posted Nov 18, 2009 at 9:37 PM | Permalink

    What do local temperature stations say? The sites in their map are centered around 38W 117N. For long standing rural temperature stations within 100 km I find 10 stations that are listed as having data from 1900-2008:

    Using Excel I can average the yearly averages of these 10 stations. I filled in occasional gaps by averaging the adjacent years.

    I don’t have the Salzer data in front of me so I’ll make a bit better Photoshop graphic to compare short term fluctuations to actual temperature:

    Here we have a one-to-one correspondence, each dot being a year. There is quite poor correspondence but if I imagine three sites having noise concerning storm damage etc. then noise it merely the problem.
    So I need longer Salzer data, going back to 1900 to confirm that the overall correspondence holds up for the entire thermometer record.

    • Jim Steele
      Posted Nov 19, 2009 at 1:54 AM | Permalink

      Re: NikFromNYC (#94),

      You ask what the local stations say and the question points to the heart of the problem. Salzer shows significant correlation with temperature and ring width only when using the

      the PRISM gridded data set of monthly surface temperature and precipitation at 4-km resolution (21) for the period AD 1895–2006 for comparison with bristlecone growth along the White Mountains elevational transect and at the upper forest border in the Snake(MWA)and Ruby (PRL) ranges in Nevada

      The upper-treeline mean ring-width chronology (GBR3) is an average of the 3 chronologies of mean ring-width from the collections at each of the 3 upper-treeline bristlecone pine sites: SHP, MWA, and PRL (Fig. 1 and 4B). The PRISM3 record of mean monthly temperature anomalies is an average of data from the 3 pixels geographically closest to the SHP, MWA, and PRL sites, each seasonalized to a previous-September-to-August mean. This seasonal window allows the inclusion of the previous autumn temperatures, thought to be important in some species for late-season photosynthesis and for influencing the next year’s growth through food storage processes (25), and the current-year summer temperature, expected to be important for radial grow that the upper forest border.

      In this mountainous terrain, within a 4 km grid a 300 to 1000 ft changes in elevation are very common. Such changes in elevations will generate several degrees of average temperature differences and those differences are typically the greatest during the growing season May -September. For example in the area where I have conducted wildlife monitoring, the average minimum July temp at Sagehen Creek,elv 6350 ft, is 37.1 F , 400 feet lower at Donner State Park, elv 5950 ft, the July minimum is 41.1 F. Remember critical thresh hold temperature for growth is estimated to be 46.4-48.2F.

      They do not define treeline by elevation. That is because the limits of treeline may also be affected substrate variables( geology, hydrology, etc), north or south facing slopes, etc. And Salzer’s definition of a transitional zone ranges over 450 feet of elevation. Using the averaged PRISM data for a 4km grid does not account for the temperature differences over the stated elevational ranges. And by categorizing the data into “above and below” the transition zone, actual temperatures are obscured, and thus does not allow for an accurate correlation between temperatures and growth. Not surprisingly within their categories, their standard deviation of the ring widths is about 50% of the mean.

      Furthermore given that Salzer also observed a contradictory switch from positive to negative correlations of temperature and ring width over elevations spans of just 300-400 feet, there again seems to be a need for a actual temperature measurements at each sample site, as well as inclusion of other environmental factors, before any robust conclusions can be determined.

      They state

      The reported critical value of mean daily temperature for the onset of wood formation is 8 to 9 °C, a value that usually is not reached until mid to late June at treeline in the White Mountains. Maximum mean daily temperatures at SHP (11 °C) commonly are not reached until late July and are only slightly greater than the minimum reported for wood formation.

      There is also a need to determine iwhat is the appropriate temperature metric. Using the maximum or average temperature may have significant problems. They neglect to discuss that during the growing season the average minimum temperature is often several degrees below this critical threshhold temperature of 46.4-48.2F for growth. So using average or maximum temperatures may be a very misleading metric, depending on the amount of time spent below the critical temperature. And again 300-450 feet of elevation change is observed to affect the minimum temperature by as much as 8 F.

      Salzer has uncovered an interesting phenomenon that shows ring width growth changes unexpectedly with elevation. It shows that warmer temperatures below the transition elevation can decrease growth, suggesting there are factors overwhelming temperature effects. The Salzer paper very clearly demonstrates that much more work needs to be done in order to understand the limiting factors of ring width before they can be reliable climate proxies . So in that regard this is an important paper. But to use this work to trumpet support for AGW when the calculated change in average global warming over the past 50 years is around 1.5 F degree, is quite speculative when the elevational differences in temperature above the transition elevation alone are far greater. But such AGW trumpeting is fashionable these days.

      • EddieO
        Posted Nov 19, 2009 at 5:01 AM | Permalink

        Re: Jim Steele (#110), You make several good points here Jim. I think the chances of retrospective temperature measurement on site are nil so robust conclusions may be impossible to extract.

      • Steve McIntyre
        Posted Nov 19, 2009 at 6:32 AM | Permalink

        Re: Jim Steele (#110),

        Salzer has uncovered an interesting phenomenon that shows ring width growth changes unexpectedly with elevation. It shows that warmer temperatures below the transition elevation can decrease growth, suggesting there are factors overwhelming temperature effects.

        This is hardly an original observation by Salzer. In the US Southwest, the existence of both an upper and lower limit is old hat – the lower limit is defined by precipitation response.

        In the 1960s, Fritts did very detailed experiments on bristlecone growth measuring daily growth against soil moisture. When soil moisture fell below a certain level, growth ceased. There is a article from the 1960s cited in MM2005(EE) which analysed the competition between bristlecone and large sagebrush, observing that soil moisture was retained longer in dolomite at a given elevation, favoring bristlecone over large sagebrush – thus the sharp demarcation at the geological contact.

  46. Posted Nov 18, 2009 at 9:40 PM | Permalink

    The stations are actually those within 330km and are Austin, Battle Mountain, Fallon, Independence, Lemon Cove, Mina, Modena, Wasco, Winnemucca Mu and Mcgill.

    • bernie
      Posted Nov 18, 2009 at 10:43 PM | Permalink

      Re: NikFromNYC (#95), Interesting. Did you look at the elevation of these stations? I believe for example that Independence, the capital of Inyo County, is in a deep valley floor.

      • Rattus Norvegicus
        Posted Nov 18, 2009 at 11:12 PM | Permalink

        Re: bernie (#101), Independence is at about 4,000ft. You have 10K to 12K peaks to the east in the Whites, and 14K peaks to the west in the Sierras (Independence is where the trailhead for Mt. Whitney is).

      • FHSIV
        Posted Nov 18, 2009 at 11:28 PM | Permalink

        Re: bernie (#101),

        Check out this link that has tabulated daily precip and temp data for WMRS facilities at Crooked Creek (~9,000′) and Mt. Barcroft (~12,000′) for the period 1955 through 1980.

  47. FHSIV
    Posted Nov 18, 2009 at 10:00 PM | Permalink


    Sorry for Off Topic, but Cerro Gordo is located in the southern Inyo Mtns. fifty or so miles south of the bristlecone study area. The mine produced substantial silver from galena and smithsonite (zinc carbonate) ores which were smelted at Keeler at the foot of the west side of the range. After the local pinyons were all gone, they constructed a flume to bring logs down from the east side of the Sierra to the kilns. Also, Cerro Gordo supplied much of the silver coined at San Francisco after the Comstock was played out.

    The history of this area is some of the best that California has to offer, including paddle wheel steam ships in now dry Owens Lake, and houses built from lead/silver ingots at the ‘port’ of Cartago. But, most interestingly of all, a guy named Nadeau, who got the contract to supply the mines, hauled the ingots to what became Port of Los Angeles for shipment to San Francisco. This is thought to have initiated the trade which contributed to the early development of the city of Los Angeles.

    • Steve McIntyre
      Posted Nov 19, 2009 at 12:18 AM | Permalink

      Re: FHSIV (#96),

      The drying of Owens Lake is mentioned in post #302, which noted that 50% of the silt in the White Mts is blown from Owens Lake, which (as I understand it) is a very large point source of silt in national terms.

  48. FHSIV
    Posted Nov 18, 2009 at 10:07 PM | Permalink

    bernie (#93),

    Yes, but old paper based stuff that I’ll have to recover from my pile. I can think of a few specifics right now, but I can put together a pretty comprehensive list given a day or two.

    • bernie
      Posted Nov 18, 2009 at 10:38 PM | Permalink

      Re: FHSIV (#97), Thanks, but I have just spent the last 30 minutes re-reading Steve and Ross’s 2005 EE paper. They put together a very good summary of what happened in this area. As Steve McIntyre (#92), suggested take a look at what they wrote – perhaps it will trigger some additional personal reflections.
      I am embarrassed that I had forgotten or not noticed the very detailed site and context descriptions included in this paper.

      • Steve McIntyre
        Posted Nov 19, 2009 at 12:16 AM | Permalink

        Re: bernie (#100),

        Some early CA posts connect information about 19th century mining to access to bristlecone sites e.g posts 406, 153. I have other information material that I’ve never posted. 406 has some very interesting old maps.

  49. FHSIV
    Posted Nov 18, 2009 at 11:19 PM | Permalink

    Bernie (#100)

    Check out this link to White Mountain Research Station’s ‘Reference Page’ that has daily temperature and precipitation data for immediately adjacent sites at Crooked Creek and Mt. Barcroft from 1955 through 1980.

  50. Geoff Sherrington
    Posted Nov 18, 2009 at 11:23 PM | Permalink

    FWIW, long-term periodic growth events are well known in the plant world.

    Further, the masting cycle of bamboo is considerably delayed (up to over 50 years) compared to most other mast producing species (3-7 years) (Platt and Brantley 1997; Keeley and Bond 1999). etc.

    Altough from a vastly different sector of the plant world, some bamboos have some behavior in common with that described in the subject paper. Large groups of bamboos flower suddenly after decades of no flowers, then in some species, die. (This might be another U-shaped growth reponse). Of course, this has an effect on predator-prey balance, which is another effect that needs mention for completeness. In a well known case from Sichuan, the Giant Panda was at risk of running out of food. In the present context, the predator might also be a pollinator, such as a tiny insect.

    It’s just another of the variables that might (stress might) have to be taken into account.

    BTY, it’s hard to tell from the movie, but the geology of the Sheep Mountain top could be different from that down among the trees. It does not look the same, but visual is a poor test.

    Today’s new word: Semelparity

    • bernie
      Posted Nov 18, 2009 at 11:35 PM | Permalink

      Re: Geoff Sherrington (#103), Geoff, Steve’s and Ross’s 2005 EE paper gives an excellent summary of the geology plus pictures – which confirms and expands upon FHSIV (#91) personal recollections.

  51. Geoff Sherrington
    Posted Nov 19, 2009 at 12:08 AM | Permalink

    Moe complications. If you go to Google Earth, there is a near-straight line, probably a fault, between 36 17 54, 118 37 37 and 36 18 13, 118 37 54 . (Deg min sec) This is about 2,900-3,000 m asl, about the same as the peak of Sheep Mountain nearby, is less than a km away from the peak and is a feature some 600 m long.

    The observation is that there is a line of trees on the southern section of this ?fault. If it is a fault, then a secondary influence is likely, like moisture retention, deeper soil profile, trace mineralisation differences, etc. These trees in a line are expected to be different from those without fault proximity. FSHIV, would like to see your geological mapping.

    BTW, this is not the only example within a 2 km of Sheep Mountain where the sparse trees line up. Two more are easily seen.

    More complications, more caries to explain before the dendro dentures go in.

    Geoffrey lecture: An essential part of a science study is the control of as many variables as possible AND THEIR REPORTING.

    • Steve McIntyre
      Posted Nov 19, 2009 at 12:22 AM | Permalink

      Re: Geoff Sherrington (#106),

      There has been some very important geological activity in this area in the last 1000 years – see Inyo Craters. This has been discussed in the past.

      As I recall, the death of high-altitude forests in the Sierras was dated by Millar et al 2006 to 1251 AD – a date that one sees in other contexts.

    • FHSIV
      Posted Nov 19, 2009 at 5:36 PM | Permalink

      Re: Geoff Sherrington (#106),


      The coordinates you gave are for an area the Sierra Nevada Mtns., well to the southwest of the Sheep Mtn. area. I’m not sure which lineations you are describing, but the mapped faults in the area of Sheep Mtn. trend northeast and the formational contacts trend northwest.

  52. Phil B.
    Posted Nov 19, 2009 at 9:28 AM | Permalink

    In 2005 I had a email discussion with John Wehausen, a researcher for WMRS who studies The Bighorn sheep in the White Mountains and S. Sierras.


    Thanks for the contact and questions. There were domestic sheep still
    being grazed on Pellesier Flats on the top of the Whites in the 1960s. On the
    east side of the Whites is an old ranch called the McNett Ranch that one passes
    on the road up Indian Creek. The current owner of the Cinnamon Ranch in Hamil
    Valley told me some year ago that he worked for McNett in the 1960s as a
    shepherd high in the Whites. Forest Service records probably would determine
    what year that grazing ended. Recently we discovered that a small bunch of
    domestic sheep have been grazed every spring on a small parcel in Chalfant
    Valley along the base of the Whites and a year ago they were documented to be
    loose in the White Mountains. This summer we had respiratory disease in the
    bighorn in that range and do not know what the outcome has been. We did count
    275 bighorn in that range in early summer.

    I think I once had a discussion with Doug Powell on Sheep Mountain and he told
    me it was named for bighorn sheep. It does makes sense habitatwise. There is
    good bighorn habitat in the canyon immediately west.


    At 07:51 PM 10/18/2005 -0700, you wrote:

    Dear Dr. Wehausen

    I enjoyed your discussion about the bighorn sheep in the video “In the shadow
    of White Mountain”. Keep up the great work. If you have the time, I had
    several questions. When did domestic sheep grazing end in the White Mountain
    area or has it? Are there still Bighorn sheep in the White Mountains or are
    they restricted to Southern Sierras? Did Sheep Mountain get its name from
    the Bighorn Sheep or the domestic sheep?

    Thanks Phil B.

  53. hengav
    Posted Nov 19, 2009 at 11:21 AM | Permalink

    Can anyone tell me if the color of each ring in any of the cores is archived along with the width? I was looking at the example from the Miracles of Strip Bark thread again. The tilted example shows reaction wood on 2 different sides that is clearly a darker color. Surely this would be a good check, no?

  54. Curt
    Posted Nov 19, 2009 at 3:32 PM | Permalink

    Malcolm Hughes was interviewed about this paper yesterday on NPR’s “All Things Considered” news show. You can listen to it here:

    • Leighton
      Posted Nov 19, 2009 at 5:17 PM | Permalink

      Re: Curt (#115),

      I listened to the NPR interview and found it odd. There was nothing wrong with the interview, per se, but the oddness was in the absence of any apparent justification for the airtime. If I had not been alert to this as a hot topic from reading this and other blogs, e.g., RC, it would not have had any apparent relevance. I think that the key from NPR’s point of view is the casually dropped remark to the effect that the growth is now attributed to 50 years of warming rather than to increased concentrations CO2. I chuckled, knowingly, at the interviewer’s wonderment at the word “dendrochronology.” For once in my life, I felt like one of the cognoscenti. :-)

  55. Wolfgang Flamme
    Posted Nov 19, 2009 at 6:21 PM | Permalink

    I just started comparing cores, using Steve’s collation of Salzer’s Sheep Mountain data. This example is more rule than exception:

  56. Jim Steele
    Posted Nov 19, 2009 at 7:16 PM | Permalink

    I find it interesting that a 1972 paper by LaMarch and Mooney 1972 (Mooney is kind of the dean of plant ecology and edited the Salzer paper) determined that 2000 thousand years ago the Bristlecone tree line was at least a 100 meters higher. That suggests that current temperatures must be substantially cooler now

  57. Don Keiller
    Posted Nov 20, 2009 at 4:18 AM | Permalink

    Looking at the data that Steve has posted up on “pdfs plotting ring width series by tree” I’m gobsmacked by the sheer amount of both between tree and within tree variation. If I, like jan Esper, had the ability to pick and chose my data, I could well make more or less any pattern it wanted.

  58. Josh Doe
    Posted Nov 20, 2009 at 11:23 PM | Permalink

    I think I should submit this to Nature:

    Based on the results of Salzer et. al, I hypothesize that the increased rate of growth is strongly correlated to profound global warming. These bristlecone pine trees are growing at an increased rate in an attempt to filter more carbon from the air in order to reverse the effects of global warming. Only the trees near the top of the tree line are so environmentally conscious, because they have the most to lose should global warming continue. If the planet does warm, then the tree line will climb, and new trees growing higher than themselves will block the sun. The increased rate of tree growth is merely an attempt to prevent new high elevation trees from destroying their monopoly on sunlight.

    Seems to be as scientifically and causally based as most of the AGW research. Someone want to peer-review this for me?

  59. Wolfgang Flamme
    Posted Nov 21, 2009 at 7:23 AM | Permalink

    Replicated Fig. S3 from SI here:

  60. Posted Nov 23, 2009 at 3:29 AM | Permalink

    From the FOIA2009 emails, on Briffa’s “serious issues” with the bristlecones. November 2006:

    Another serious issue to be considered relates to the fact that the PC1 time series in the Mann et al. analysis was adjusted to reduce the positive slope in the last 150 years (on the assumption – following an earlier paper by Lamarche et al. – that this incressing growth was evidence of carbon dioxide fertilization) , by differencing the data from another record produced by other workers in northern Alaska and Canada (which incidentally was standardised in a totally different way). This last adjustment obviously will have a large influence on the quantification of the link between these Western US trees and N.Hemisphere temperatures. At this point , it is fair to say that this adjustment was arbitrary and the link between Bristlecone pine growth and CO2 is , at the very least, arguable. Note that at least one author (Lisa Gaumlich) has stated that the recent growth of these trees could be temperature driven and not evidence of CO2 fertilisation

    It is interesting to me that some of these folks don’t believe that CO2 has any growth effect. Others have decided that it’s only short term, in defiance of the FACE and other experiments. But in any event, Keith Briffa’s complaints seem to provide support for Mr. McIntyre’s observations.

    ===|==============/ Level Head

  61. EdeF
    Posted Aug 5, 2010 at 1:19 AM | Permalink

    I finally had a chance to read the full report at leisure, look into some of
    their assumptions and have found several things to take issue with. If ClimateGate hadn’t broke right at the time of this report we may have delved into it much more. The first thing that I noticed was that there is no attempt to standardize the tree ring data. This is raw tree data. But the report does not say what age the various trees are that make up this study. (Have found that they have, surprise, archived some of the data). Are they comparing trees of a similar age? Do the high altitude trees include ones that are younger, and
    therefore have wider ring growth in youth? I am very perplexed by this, and by the fact that the higher altitude trees have much larger growth than the trees
    at Methusulah Walk, which should be in the sweet spot of optimal conditions
    for growth, unless the trees sampled there are ancient. Don’t know how this
    got past the peer reviewers, the fact that there is no standardization. The other thing is that they say there is no divergence between the temperature
    reference and the ring widths until 1950 is a laugh. Looks like things are
    starting to diverge much earlier than that. I see no place where it is spelled out what stations are used for the temperature references. All of the stations
    surrounding the White Mountains show the typical, mundane NH temperature trends
    in the 20th century. There seems to be a divergence between the local temperatures and the ring growth at very high altitudes. On top of this, I have read Steve’s comments above and those are of primary concern.

    • EdeF
      Posted Aug 6, 2010 at 2:06 PM | Permalink

      Have started to look at the individual tree ring data for the lower elevations at Methusulah Walk at Schulman Grove. Tree 93012A data starts at 1400 and
      goes to mid 1990s. I don’t know how old this tree is in 1400, have no location
      nor a picture of the tree. Don’t know if it is strip bark or not. For most of
      the 600 period the ring data is fairly flat like that shown in the report for
      the lower altitude trees. Data oscillates about the average data. But in the
      late 1700s the tree rings increase dramatically about the time of the LIA. I
      don’t know if this is because colder temps in the region have caused more ice
      and snow leading to tree damage, then strip barking, or if as the temperature
      cools, these trees once heat stressed are now operating in their optimal growth
      region? The plot of this tree looks almost upside down from typical reconstruction plots. It also looks like their are (to the naked eye) 30 and
      70-yr oscillations from the average. After the LIA highs the plot decays down to the long-term average ring sizes.

      I am not sure why they don’t plot the actual weather station average temperature data but have used as reference late season density data? What don[‘t they want to show about the station data? I have been getting local wx station data from Bishop airport and other locations, transforming them to MWK
      altitudes (latitude is the same so no translation there) and those plots look
      fairly flat for the 20th century.

      • EdeF at Schulman Grove
        Posted Aug 11, 2010 at 12:42 AM | Permalink

        Have just plotted some of the higher altitude trees at Sheep Mtn just during the modern era (last century) and some surprises there. In one
        tree the ring widths max out in about 1970 and then downhill from there,
        in the other one it peaks about mid 1930s then steep downhill. If I plot
        these data vs temperature its a scatter plot……looks like someone was
        testing a new bird gun. Nothing like a linear trend. Same for the lower
        elevations, its pheasant hunting time. Reminds me of when JeffID went
        hunting last Nov. when Climategate broke. Have not found a lot of data
        that goes all the way to the 2000s. Now, the report says that the last
        50 yrs was the highest, but they seem to leave out that it looks like
        there is a loss of response in the latest decades. It very well could be
        that high temps are causing the trees to operate out of the optimum zone.
        Let’s check that out, but don’t do any slight of hand that does away with
        this. Remember, if we lose sensitivity in the 90s and 00s, the same could
        be said for some times in the past. Goose and gander. By the way, what
        is the lowest elevation that BCPs have existed in the White Mtns since the last ice age? If we find historic remnants of BCPs at say 8,000 ft
        elevation, should indicate a much colder environment.

        • EdeF at Schulman Grove
          Posted Aug 16, 2010 at 11:05 PM | Permalink

          Have been comparing various weather stations in a large area surrounding the BCPs on White Mtn, compared the short-spanned White Mtn
          stations with Bishop Airport, Independence, Reno and Las Vegas, NV,
          Victorvile, Ca and LAX and SEATAC airports. Believe it or not, all of the Eastern California and Western Nevada wx stations correlate very well with each other when altitude and latitude are accounted for. This should not be too much of a surprise since all of these stations are
          inland, upper elevation stations that are very dry, cloud free for most of the year with super low humidity and little fog. I did see some uptick in the temperatures in the last 15-20 years in Vegas and Victorville relative to the more remote sites. Not sure if this is UHI, increased lawns or ? Temperatures at LAX, Seattle and Huntington
          Lake on the west side of the Sierras are boringly flat and uninteresting and don’t correlate with the others. I think I can move the instrumented period back a little bit by using some of these stations that go back prior to WWII with appropriate latitude and
          altitude corrections. Unfortunately, there was little civilization in
          this part of the world before WWII. There is barely enough years for
          the calibration period, not sure how they did the verification back into the 1800s?


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