date: Mon, 27 Sep 1999 12:39:40 -0400
from: Brian Luckman <luckmanatXYZxyzian.uwo.ca>
subject: Re: northern network(s)
to: Keith Briffa <k.briffaatXYZxyz.ac.uk>
You may find the attachment of interest. Keep me updated on this.
Unfortunately I am rather preoccupied just now with my daughter's wedding
We have 6 new density chronologies from high elevation in southern BC and a
reconstruction back to 1600 which follows the Icefields curve but also has
problems in the late 20th century in modelling temperature increase- but
the problem apppears to be ringwidth ( more anon)
I have forwarded your message to Glen
Any movement on the Precip reconstruction paper?
t 04:37 PM 9/27/1999 +0100, you wrote:
>>27 September 1999
>>I thought it worthwhile to mention an idea that I, and Fritz Schweingruber,
>>have been considering for a while: namely the need to update the circum
>>network of tree-ring chronologies.
>>All of you have strong research interests in northern boreal forest and it
>>seems to me that we might all share a mutual interest and benefit from
>>discussing the options on how to achieve this. Our own work, as you know,
>>indicates a puzzling drift in the decadal timescale correspondence between
>>falling density values and rising summer temperatures, most apparent in
>>years leading up to the 1980s. This is juxtaposed with a longer rising
>>in basal areas, apparent from around the middle of the 19th century, but
>>seems to have largely stabilized again in the later part of the current
>>century. What are believed to be unprecedented levels of global warmth
>>say in a 1000-year context) are manifest in the last decade or so (though
>>details of high latitude warming are open to discussion). This fact alone
>>demands that we explore the nature of tree-growth/climate responses in
>>recent decades as extensively as possible. The opportunity to explore
>>time-dependent growth responses and validate previously calibrated transfer
>>functions against certainly unusual background conditions (i.e. increased
>>anthropogenic influence) all point to an urgent need to update our mutual
>>growth data. The work 'mutual' might bring a wry smile to some faces as
>>also clear that we have all, for the most part, followed our individual
>>dendroclimatic paths up until now!
>>This brings me to the CAPE (Circum Arctic Palaeo Environments) project:
>>in principle this incorporates a high-resolution component, in practise it
>>not, for whatever reason, had any meaningful focus on, or given much
>>to, high-resolution (read especially dendroclimatic) research.
>>I do not know what all of your most recent priorities are, but for our part
>>(Fritz, myself, and hopefully Stepan and Eugene) we see the need to
>>development of a circum Arctic tree-ring (densitometric) network and a
>>improve and update major parts of it. Presumably, many of you think
>>even if your own interests do not directly revolve around tree-ring-density
>>data. In the next few months, I (and a number of the addressees of this
>>message) will be planning an approach to the European Community to support
>>work that might enable us to achieve some of this in Europe and Siberia.
>>are also considering how this might also best be done in the U.S. and
>>Also, what about somewhat more southerly (but strongly temperature
>>sensitive) regions such as western U.S., Tibet, European Alps and Mongolia?
>>Is it time to consider a combination of our resources or some form of
>>coordinated approach to multiple funders? We have different approaches,
>>opinions, geographical priorities, etc. etc. However, there are surely
>>scientific and practical advantages in considering a more integrated
>>The Canadian government, the new PARCs initiative and existing NSF funding
>>sources could probably all be tapped by many of you in N. America. As I
>>we will be approaching the EC. What about considering linked proposals?
>>are the data exchange implications? Would some of you with densitometric
>>equipment be willing to collaborate with Fritz and Eugene in updating
>>some sites (Eurasian or N. American or whatever) and exploring recent
>>(potentially age-dependent) changes in densitometric responses across the
>>network? The development of longer (Holocene) records of tree-growth
>>and tree-line change would surely benefit from closer collaboration across
>>between continents. I throw this out to see what you think.
>BY THE WAY -
> I just sent this to people whose addresses I had to hand - e.g. I could
>not find an address for Glen McDonald- and you may think others would be
>interested, so feel free to forward it if you think it appropriate.
>>the best to all,
>Dr. Keith Briffa, Climatic Research Unit, University of East Anglia,
>Norwich, NR4 7TJ, United Kingdom
>Phone: +44-1603-592090 Fax: +44-1603-507784
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