Esper et al [2002]

Esper et al [2002] divides trees into "linear" and "nonlinear" trees depending on their growth – a classificaiton that is idiosyncratic to this publication as far as I can tell. Esper at al. [2002] provides a citation to a publication "in press" that supposedly explains this, but I can’t locate any explanation in the publication. Perhaps I’m missing something in plain sight, but I don’t think so.

Esper et al [2002] says:

To build RCS chronologies from the whole data set that contains different sites and species, we analyzed the growth levels and trends of the individual ring-width series after aligning them by cambial age and classifying them into two groups: one with age trends that have a weakly “linear” form (443 series) and one with age trends that are more “nonlinear” (762 series) (8). The data sets were divided this way because differences in growth levels and slopes can bias resulting RCS chronologies (21). For example, according to their mean age trends (8), the young nonlinear trees grow 2 to 3 times faster than the linear trees up until 200 years of age.

The references are :
8. Supplementary details are available on Science Online at
21. J. Esper, E. R. Cook, K. Peters, Tree-Ring Res., in press.

I have been unable to identify anything that corresponds exactly to citation (21), but I presume that this is Esper, Cook , Krusic, Peters and Schweingruber, Tree Ring Res. [2003]. online here , which I’ve been discussing in connection with Gotland.

As evidenced by most posts on Gotland, it’s pretty obvious that I’ve been reading this article carefully. The pdf doesn’t search unfortunately. Visually I can find no reference to the linear/non-linear distinction. Thus, this key distinction remains unaccounted for: another frustrating Hockey Team publication in Science.


  1. TCO
    Posted Sep 13, 2005 at 8:22 PM | Permalink

    Science is really looking bad by allowing all this forward citation of methods.

  2. Steve McIntyre
    Posted Sep 13, 2005 at 9:50 PM | Permalink

    Jones and Mann [2004] in Reviews of Geophysics slagged MM03, citing MBH, submitted to Climatic Change – another forward citation. MBH, submitted, was then rejected by Climatic Change – whose editor is Stephen Schneider, no friend of our critique – so you can assume that our rebuttal to MBH’s submission was very strong indeed.

  3. John A
    Posted Sep 14, 2005 at 2:25 AM | Permalink

    Or, just as importantly, Mann’s “refutation” must have been very weak indeed.

  4. Paul Gosling
    Posted Sep 14, 2005 at 2:59 AM | Permalink

    I am probably showing my lack of competence in statistics here (again). But if some trees show linear growth and some not,is it not reasonable to assume there are two ‘populations’, therefore making sense to analyse them seperately?

  5. Steve McIntyre
    Posted Sep 14, 2005 at 5:26 AM | Permalink

    The distinction between "linear" and "nonlinear" growth is a novel one – I don’t know what it means operationally. I’ve looked at hundreds of plots of tree cores and I find it hard to even speculate on what it means. It obviously has to do with the amount of juvenile pulse, but there are a lot of cores with no juvenile pulse. Waking up on this, not only does the supposed citation not explain the linear/nonlinear distinction, but it calculates RCS for Gotland without applying this distinction. Rather than speculating on this, I think that I’ll write another letter to Science pointing out that the forward citation did not do what it was supposed to do and requesting a detailed SI explaining what they actually did. I’m not very optimistic – this is hard core Hockey Team and a key popularizer, but you never know until you ask.

  6. TCO
    Posted Sep 14, 2005 at 5:39 AM | Permalink

    Forward citations are tricky (because you may not get accepted, because you may abondon the paper, etc.) thing. I’ve done them myself, mostly for purpose of plugging myself. If you do divide things into LPUs, you may have some times where you want to do so, to point out a related interesting matter and to plug yo bad self. However, a forward citation OF METHODS or of a main support for an argument. That is poor practice. Should be caught by the reviewer.

  7. TCO
    Posted Sep 14, 2005 at 5:42 AM | Permalink

    Yes, you should send a respectful request for clarification/correction (even if it doesn’t give you satisifaction…these things add up).

  8. Steve McIntyre
    Posted Sep 14, 2005 at 6:43 AM | Permalink

    I’m pretty good about writing these sorts of letters. I seldom get anywhere, but, I’ve learned long ago, that if you don’t ask, they can say that you didn’t ask.

  9. Armand MacMurray
    Posted Sep 14, 2005 at 10:11 AM | Permalink

    I would expect that the original submission to Science would have included copies of any “in press” citations for the reviewers’ use. Perhaps Science still has such; in any case, in order to observe scientific niceties, why not try writing Esper first with the request for methodology info? Continuing with such requests, even if they end up being only pro forma, can only help your image and reputation. Who knows — one of the requests might actually work, too!

  10. TCO
    Posted Sep 14, 2005 at 12:53 PM | Permalink

    I’ve written for the literature and had citations that were in press or even “submitted” (good to be clear and honest about the difference, if it’s still in review, it may not get accepted and “in press” is not legit.) I think I’ve even seen or done citations that were not written yet (you can also cite stuff as “unpublished”) but going to be written and submitted to a journal. But in those cases it was always for tangential matters, interesting to a reader…but not part of the key methods.

    In any case, I’ve never seen (or done) someone give copies of unpublished citations. That stuff has tended to be on trust, in my experience. Of course, it is not a good practice…for the obvious reason that plans change and things don’t get published. But anyone who’s looked at papers has had the frustrating experience of mistaken citations anyway even for the publisehd lit (not justifying it…prefer the opposite…just my experience).

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  1. By The Global Warming Bollocks | JustGoFaster on Jul 26, 2011 at 9:36 AM

    […] Esper et al 2005 compared previous studies and the diagram below shows their findings. […]

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