cc: stepan@ipae.uran.ru, eavaganov@forest.akadem.ru date: Mon Feb 4 09:56:12 2002 from: Keith Briffa subject: Re: Tree growth/ uV link? to: "Svetlana Bondarenko" Dear Professor Zuev I am very interested to see that you are also looking at the possibility that uV radiation increases at high latitudes might be impacting on tree-growth. Along with several colleagues here and in Switzerland (Fritz Schweingruber) , along with Academician Vaganov and Professor Shiyatov from your country, I have been very interested in the apparent changing relationship between measured tree growth (ring width but particularly ring maximum density) and summer temperature - not just in Russia but also in other relatively high-latitude or high-elevation sites in the U.S. , Canada and Europe. We have established that there is a slow change , with the link between these data weakening over the last 50 years , but year to year changes on a large scale staying parallel. I have suggested in several conferences and in press that higher uV (as a consequence of reduced total ozone ) may be factor , but this is speculation based on some reading of the physiological literature that suggests that photosynthetic processes may be impaired in high uV experiments. There is also the coincidental observation of reducing ozone at some long record sites (such as Arosa) since the 1950s. However, other environmental variables , e.g. the atmospheric clarity, also show negative trends over this period, so there can be little statistical evidence offered . We have though tried looking in some detail at the association between temperature residuals (that is the difference series between our empirical estimates of temperature change as calculated from tree-growth , and observations of summer mean temperatures) across the different parts of our network , and variations in total ozone as extracted from the TOMS satellite data . This is intriguing but not convincing ( we would hope to see a positive correlation ) - but in many areas our tree-ring data (especially the density data) do not come up to the present and the satellite records are short (only from the late 1970s) so again our degrees of freedom are low for this comparison. This later work is not published but I will send a few references to our earlier papers , and in the meantime I will read the text that you have sent me. Please be a little patient as I am very bogged down with several passed deadlines and teaching at present. Very best wishes Keith At 03:21 PM 2/1/02 +0800, you wrote: Dear Doctor Briffa, Quite recently, our results concerning the reconstruction of paleobehavior of ozonosphere from dendrochronologic wood density data were presented at the international conference «Ecology of Siberia, the Far East and the Arctic» in Tomsk, and a little later at the Sukachev Institute of Forest in Krasnoyarsk. These results have stirred real interest. Academician Vaganov, Director of Institute of Forest, referred to your papers, and prompted that it is you who pointed out to some mismatches appearing between dendrochronologic time series and temperature/precipitation variations, and who related dendrochronologic data to some other parameters such as ozone concentration. May be our results will be of interest for you. So, we send you a translation of our paper published in: Environment of Siberia, the Far East and the Arctic: Selected papers presented at the International Conference ESFEA 2001, Tomsk, Russia. September 5-8, 2001. P 3-12, V. V. Zuev and Yu. P. Turov, Editors. We would be indebted if you respond to our results in order to bridge scientific contacts in development of this branch of dendrochronology. Academician Vaganov, who discussed this problem with us, also considers it useful to contact you. Our research area is the study of stratospheric changes using the laser sensing methods, primarily by studying the changes in ozonosphere (Laboratory of Remote Spectroscopy of the Atmosphere, http://eng.iao.ru). We are strongly interested in problems of natural variability of ozonosphere. Unfortunately, in the field of dendrochronology, we are only making first steps, having few sources of the corresponding dendrochronologic data. In particular, from the paper it is clear that ozone is found to be most strongly correlated with density of Stone Pine in Arosa, Switzerland; whereas other data for this tree species for other geographic regions are very difficult to find. Possibly, there may be some other types of sensitivity to the effect of UV-B radiation. We would be very indebted if you give us the corresponding bearings in this direction. Prof. Vladimir V. Zuev, Corresponding Member of the RAS Svetlana L. Bondarenko, postgraduate students Fax: 7-3822-25-83-85. E-mail: [1]bondarenko@iao.ru -- Professor Keith Briffa, Climatic Research Unit University of East Anglia Norwich, NR4 7TJ, U.K. Phone: +44-1603-593909 Fax: +44-1603-507784 [2]http://www.cru.uea.ac.uk/cru/people/briffa[3]/