Friday, May 4, 2012


date: Mon, 27 Sep 1999 15:18:46 +0100 (GMT Daylight Time)
from: Julie Burgess <>
subject: 2nd email

Here is the second email Keith.

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 Arctic
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 the 30
years leading up to the 1980s. This is juxtaposed with a longer rising trend
in basal areas, apparent from around the middle of the 19th century, but which
seems to have largely stabilized again in the later part of the current
century. What are believed to be unprecedented levels of global warmth (let's
say in a 1000-year context) are manifest in the last decade or so (though the
details of high latitude warming are open to discussion). This fact alone
demands that we explore the nature of tree-growth/climate responses in the most
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 it is
also clear that we have all, for the most part, followed our individual
dendroclimatic paths.

This brings me to the CAPE (Circum Arctic Palaeo Environments) project: though
in principle this incorporates a high-resolution component, in practise it has
not, for whatever reason, had any meaningful focus on, or given much direction
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 continue
development of a circum Arctic tree-ring (densitometric) network and a need to
improve and update major parts of it. Presumably, many of you think likewise,
even if your own interests do not directly revolve around tree-ring-density
data. In the next few months, I (with Fritz, Stepan, Eugene and others) will
be planning an approach to the European Community for support for selective
work that might enable us to achieve some of this in Europe and Siberia. We
are also considering how this might also best be done in the U.S. and Canada.
Also, what about crucial, somewhat more southerly (but strongly temperature
sensitive) regions such as western U.S., Tibet, the European Alps and Mongolia?
Is it time to consider a combination of our resources or some form of
coordinated approach to multiple funders? I know we have different approaches,
opinions, geographical priorities, etc. etc. However, there are surely
scientific and practical advantages in considering a more integrated future.
The Canadian government, the new PARCs initiative and existing NSF funding
sources are probably all being tapped by many of you in N. America. As I said,
we will be approaching the EC. What about considering linked proposals? What
are the data exchange implications? Would some of you with densitometric
equipment be willing to collaborate with Fritz and I and Eugene in updating
some sites (Eurasian or N. American or whatever) and exploring recent
(potentially age-dependent) changes in densitometric responses across the wider
network? The development of longer (Holocene) timescale records of tree-growth
and tree-line change would surely benefit from closer collaboration across and
between continents. I throw this out to see what you think.

the best to all,

Keith Briffa

Julie Burgess
Climatic Research Unit
University of East Anglia
Norwich NR4 7TJ
Tel. +44 (0)1603 592722
Fax. +44 (0) 1603 507784
CRU web site:

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