Tree Ring Circus

November 16, 2009

All the exceptionally well-qualified amateur dendrochronologists who regularly visit this site will no doubt have heard that a bunch of old trees have been given a shot of climatic growth hormone.  Turns out, they’ve grown faster in the past 50 years than they have in 3.7 millenia. Hear that? Millenia!

“This is a cautionary tale,” says Michael Mann, who uses tree rings to gain insights into past climates at Pennsylvania State University’s Earth System Science Center, most famously to create the “hockey stick” graph showing an increase in temperature. “Only the human impact of increasing greenhouse gas concentrations can explain that warming.”

Oh. No. You. Di’int.

Judging from past controversy, thems fightin’ words. (I anticipate a McIntyre response in less than 12 parsecs.)

On another front, this anti-millenarian discovery looks to be a sure sign that higher concentrations of CO2 are good for old-growth forest health. Yippie! An upside to coal. Looks like we can relax. Indeed, according to some ways of viewing things, maybe the correct environmental position is the position that pumps tons of sweet carbon liquor into the puckering stomata of our dear Gaia.


  1. “… in about 12 parsecs”

    That would be a neat trick if he pulled it off:

  2. Dunna, Eli thinks it will be a much smaller distance.

  3. Yes, it will be so vast that only angstroms can contain it.

  4. But, but, but!!!! Hockey stick smashed!!!! McIntyre, NRC report, Wegman, Barton, Inhofe!!!!!!!!!!!!!!

    • There are indeed “buts”. But since you have attempted to poison the well, you’ll have to forgive my lack of interest in responding directly to you.

  5. says Iain Robertsonof the School of the Environment and Society at Swansea University in Wales. “Temperature only explains about a quarter of the variance in ring-widths
    Let’s talk about this, shall we?

  6. Jeezus. That’s what a parsec is? I had no idea. I thought it was a measure of time; and a very small one at that. Given this information, I’m afraid I have to agree with the bunny.

  7. It is all Han Solo’s fault.

  8. Ok, so I guess the only place for serious discussion is going to be Climate Audit? Fine.

  9. “a sure sign that higher concentrations of CO2 are good for old-growth forest health”
    “Sure sign?” Do you make a habit of such uncritical acceptance of propositions in your academic work? If not, then why start now?

  10. Depends what you mean by ‘serious’.

  11. Well, not all “growth hormone shots” are climatic in origin. So let’s start there. A serious discussion would have us list all the things that could result in a “growth hormone shot” and start ranking which ones have the strongest evidence and are most plausible. Then we would look at this empirical model that posits that a paltry 1/4 of the variation in tree rings is attributible to temperature and discuss sources of error in this model as they relate to all those things that we listed could be producing a “growth hormone shot”. What explains the other 3/4? And is that 3/4 more like 4/5?
    Anything less would IMO be a non-serious discussion.

    • And because none of us, including you, are subject area experts able to make an independent determination about any of that, the value of such an exercise would be what (beyond checking for arithmetic errors, that is)?

      • Dodge.

      • How seriously does the paper address other factors that OTHER EXPERTS have identified that limit treeline tree growth? For example, does it sweep aside the mathematical problem of nonlinear responses to temperature and the confounding effects of moisture availability and other scarring disturbances? It doesn’t take exceptional specialization to judge whether a topic such as this has been dodged or glossed over in such a straightforward paper.

  12. I’m more interested in the implications of the finding, true or not, to a few branches of argument. In my line of work, claims don’t have to be true to be useful or interesting. Just the other day I was imagining a case in which a poor little kitten is injected straight in its brain — thwack! — with a newfangled drug, thereby resulting in the terrifying yet fascinating possibility that said kitty suddenly takes on the mental attributes of a person.

    Me. Yow.

  13. Thought a link might be useful. I’d say pinus longevea has been cleared of all charges.

    • Before uncritically accepting this offering, my advice is to watch for the scientific counterpunch from Climate Audit. It usually stings.

      • Sting like a butterfly, float like a bee.



      • Seriously, that it’s an expected “scientific counterpunch” is just the problem with the “auditors.” It’s not science for them, it’s a contest.

        Ironically, while tree-ring studies remain interesting, the “auditors” have missed all the sediment-based “hockey sticks” studies that constitute a vastly stronger basis for action. How’d it happen?

  14. I’m no subject area expert but I’d say this has some fascinating implications:

    “The lack of a substantial difference in ring width between our strip-bark and whole-bark groups in the modern period appears to contradict the finding of Graybill and Idso for the same species in the same mountain range. In fact, when their raw ring widths are plotted in the same manner as our Fig. 3, there is little difference between their strip-bark and whole-bark groups in the modern period. 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. 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 should be reevaluated.”

    Yow indeed.

    • You admit you’re no expert, yet you feel free to trumpet this result as though it were definitive. How interesting.

      • Fascinating implications are definitive? Only in Audit-land.

  15. The Salzer paper is interesting. It appears to be a direct response to McIntyre & McKitrick 2005 (E&E). I’m therefore rather uncomfortable with Salzer’s failure to cite M&M.

    • What matters is not who they cite or what inspired the study, but what the study says materially about the problem. And if anyone thinks Matthew Salzer has spoken the last word on the subject, they’d be wrong. Stay tuned …

      • Of course. Just saying.

  16. Actually, higher levels of CO2 probably would be good for old-growth forests. The trees need it to grow; nurseries typically increase levels of CO2 to promote growth, and it doesn’t become dangerous to animal life until it reaches about 8,000 ppm.

    Based on past history (in millions of years), I think this planet would be wonderfully lush, green, and warm (think Hawaii) with much higher levels of CO2.

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