date: Mon Oct 12 12:10:26 1998
from: Keith Briffa <k.briffa@uea.ac.uk>
subject: copy to a safe place!!and leave original there
to: i.Harris@uea

>Return-path: <rashit@ipae.uran.ru>
>Envelope-to: f023@cpca11.uea.ac.uk
>Delivery-date: Mon, 12 Oct 1998 08:27:00 +0100
>Date: Fri, 9 Oct 1998 19:17:12 +0500
>From: Rashit Hantemirov <rashit@ipae.uran.ru>
>Reply-To: Rashit Hantemirov <rashit@ipae.uran.ru>
>Organization: IPAE
>Priority: Normal
>Return-Receipt-To: rashit@ipae.uran.ru
>X-Confirm-Reading-To: Rashit Hantemirov <rashit@ipae.uran.ru>
>To: Keith Briffa <k.briffa@uea.ac.uk>
>Subject: Short report on progress in Yamal work
>
>Dear Keith,
>
>I apologize for delay with reply. Below is short information about
>state of Yamal work.
>
>Samples from 2,172 subfossil larches (appr. 95% of all samples),
>spruces (5%) and birches (solitary finding) have been collected within
>a region centered on about 67030'N, 70000'E at the southern part of
>Yamal Peninsula. All of them have been measured.
>
>Success has already been achieved in developing a continuous larch
>ring-width chronology extending from the present back to 4999 BC. My
>version of chronology (individual series indexed by corridor method)
>attached (file "yamal.gnr"). I could guarantee today that last
>4600-years interval (2600 BC - 1996 AD) of chronology is reliable.
>Earlier data (5000 BC - 2600 BC) are needed to be examined more
>properly.
>
>Using this chronology 1074 subfossil trees have been dated. Temporal
>distribution of trees is attached (file "number"). Unfortunately, I
>can't sign with confidence the belonging to certain species (larch or
>spruce) of each tree at present.
>
>Ring width data of 539 dated subfossil trees and 17 living larches are
>attached (file "yamal.rwm"). Some samples measured on 2 or more radii.
>First letter means species (l- larch, p- spruce, _ - uncertain), last
>cipher - radius. These series are examined for missing rings. If you
>need all the dated individual series I can send the rest of data, but
>the others are don't corrected as regards to missing rings.
>
>Residuary 1098 subfossil trees don't dated as yet. More than 200 of
>them have less than 60 rings, dating of such samples often is not
>confident. Great part undated wood remnants most likely older than
>7000 years.
>
>Some results (I think, the temperature reconstruction you will done
>better than me):
>
>Millennium-scale changes of interannual tree growth variability have
>been discovered. There were periods of low (5000-2800 BC), middle
>(2800-1700 BC) and high interannual variability (1700 BC - to the
>present).
>
>Exact dating of hundreds of subfossil trees gave a chance to clear up
>the temporal distribution of trees abundance, age structure, frequency
>of trees deaths and appearances during last seven millennia.
>Assessment of polar tree line changes has been carried out by mapping
>of dated subfossil trees.
>
>According to reconsructions most favorable conditions for tree growth
>have been marked during 5000-1700 BC. At that time position of tree
>line was far northward of recent one.
>[Unfortunately, region of our research don't include the whole area
>where trees grew during the Holocene. We can maintain that before 1700
>BC tree line was northward of our research area. We have only 3 dated
>remnants of trees from Yuribey River sampled by our colleagues (70 km
>to the north from recent polar tree line) that grew during 4200-4016
>and 3330-2986 BC.]
>This period is pointed out by low interannual variability of tree
>growth and high trees abundance discontinued, however, by several
>short (50-100 years) unfavorable periods, most significant of them
>dated about 4060-3990 BC. Since about 2800 BC gradual worsening of
>tree growth condition has begun. Significant shift of the polar tree
>line to the south have been fixed between 1700 and 1600 BC. At the
>same time interannual tree growth variability increased appreciably.
>During last 3600 years most of reconstructed indices have been varying
>not so very significant. Tree line has been shifting within 3-5 km
>near recent one. Low abundance of trees has been fixed during
>1410-1250 BC and 500-350 BC. Relatively high number of trees has been
>noted during 750-1450 AD.
>There are no evidences of moving polar timberline to the north during
>last century.
>  
>Please, let me know if you need more data or detailed report.
>
>
>Best regards,
>Rashit Hantemirov                          
>
>Lab. of Dendrochronology
>Institute of Plant and Animal Ecology
>8 Marta St., 202
>Ekaterinburg, 620144, Russia
>e-mail: rashit@ipae.uran.ru
>Fax: +7 (3432) 29 41 61; phone: +7 (3432) 29 40 92
>Attachment Converted: "c:\eudora\attach\yamal.rwm"
>
>Attachment Converted: "c:\eudora\attach\Yamal.gnr"
>
>Attachment Converted: "c:\eudora\attach\Number"
>
