From: stepan <stepan@ipae.uran.ru>
To: k.briffa@uea.ac.uk
Subject: Manuskript of papes
Date: Tue, 4 Jul 2000 11:30:39 +0600
Reply-to: stepan <stepan@ipae.uran.ru>
Cc: t.osborn@uea.ac.uk

Dear Keith and Tim,

Thank you for the papers which I have received some days ago. They
produced an impression on me. It is really a big job. I do not have
time now to evaluate in details the results obtained. I want to make
two remarks only.

First, I think, that the method of standardisation is very
interesting, but it is disputable for the regions and sites where
trees grow under extreme climatic conditions, for example at the polar
timberline in Siberia. In such conditions the shape of age curve and
the age of maximum growth are very changeable in different trees
growing at the same site. It will be very interesting if you can
present the age curve obtained for one such site, for example for the
North Taymir Peninsula.

Second, I do not agree that in the northern Siberia the 15th century
summers were warmer than those observed in the 20th century, at least
in the Western and Middle Siberia. May be it is a result of
stundartisation?

We suggest to inscibe in list of references the next papers:

1. Vaganov E.A., Shiyatov S.G., Mazepa V.S. Dendroclimatic study in
Ural-Siberian Subarctic. - Novosibirsk "Nauka", Siberian 
Publishing Firm RAS, 1996. - 246 p. (in Russian).

2. Mazepa V.S. Influence of Precipitations on Tree-Ring Growth of 
Coniferous in Subarctic Regions of Eurasia //Lesovedenie, No. 6, 
1999. - P.14-21. (in Russian).

Abstract. Influence of precipitation on tree-ring variability of coniferous 
trees in Subarctic regions of Eurasia has been shown. Depending 
on the region, significant ecological factor for tree growth are 
precipitation of autumn-winter, winter-spring and summer periods. 
Ecological explanation of such influence has been given. On the 
base of relationships between tree-rings and rainfall the 
reconstructions of precipitation in different regions of 
Subarctic for last 200 years have been developed.  

3. Mazepa V.S. Spatial Reconstruction of Summer Air Temperature in the North of 
the West Siberia since 1690 on the base of Tree-Ring Data.  
//Siberian ecological journal, No. 2, 1999. - P.175-183. (in Russian).

Abstract. Opportunity of annual reconstruction of  summer thermal 
conditions from Polar Urals (64-68°N, 64-68°E) up to Yenisei 
River (66-70°N, 86-89°E) is caused by high and sufficiently 
stable relationship between coniferous tree growth (Larix 
sibirica, Picea obovata) and corresponding climatic factors. 
Percent variance in tree-ring chronologies explained by climate 
(June-July temperature) in this extreme for growth of trees area 
reaches 50%.  Spatial reconstruction of air summer temperature on 
the base of point reconstruction for 11 corresponding 
meteostations has been developed. Analysis of reconstructed 
temperatures has shown their significant changes for last 300 
years. The most strong fall of temperatures was observed in XIX 
century, but rise in temperature was observed in XVIII and XX 
centuries.  

4. Mazepa V.S. Dendroclimatic reconstructing air summer temperatures since  1690 
in subarctic regions of siberia.  //Problems of ecological 
monitoring and ecosystem modelling, Volume XVII. - St.Petersburg 
Gidrometeoizdat, 2000. - P.170-187. (in Russian).

Abstract.  The further development of many-year dendroclimatic 
study carried out in subarctic regions of Siberia and on the 
polar timberline, is given in this paper. Climatic factors 
determining the year-to-year and many-yeared tree-ring width 
variability were revealed, using multiple regression models. The 
spatial year-to-year reconstruction of air summer temperatures 
was made on the base of available dendroclimatic network. The 
reliability of spatial summer temperatures reconstruction in the 
boreal zone of the Urals and Siberia was evaluated. The temporal 
dendroclimatic zoning of the area investigated was carried out 
according to the chronology similarity. The regional border 
changes, depending on warm and cold periods, were shown. Five 
regional chronologies showing the nature of summer months thermic 
regime variability were developed. Extremely cold and warm 
periods were revealed. The coldest periods are: the first half of 
XVII and XIX centuries. The warmest periods are: the second half 
of XVII, XVIII and middle of XX centuries.

To-day R. Hantemirov and A. Surkov will go to the Yamal Peninsula for
subfossil wood collecting. I and V. Mazepa will go to the Polar Ural
Mountains in some days.

Best regards,
 Stepan                          mailto:stepan@ipae.uran.ru




