date: Thu May 4 01:03:24 2000 from: Keith Briffa subject: Re: Question about Nature Paper to: Werner Kurz Dear Werner reply to your message in attached WORD file. Data you request are Data from final panel (ALL) of Briffa et al. (1998) All data have been smoothed with a decadal filter Year Apr-Sep T Density 1881.000 -0.648 -0.338 1882.000 -0.739 -0.599 1883.000 -0.779 -0.864 1884.000 -0.728 -1.024 1885.000 -0.567 -0.942 1886.000 -0.355 -0.655 1887.000 -0.182 -0.356 1888.000 -0.085 -0.203 1889.000 -0.081 -0.227 1890.000 -0.179 -0.355 1891.000 -0.314 -0.442 1892.000 -0.366 -0.392 1893.000 -0.273 -0.252 1894.000 -0.075 -0.126 1895.000 0.142 -0.040 1896.000 0.308 0.036 1897.000 0.359 0.066 1898.000 0.259 -0.016 1899.000 0.049 -0.153 1900.000 -0.208 -0.221 1901.000 -0.486 -0.207 1902.000 -0.701 -0.165 1903.000 -0.717 -0.098 1904.000 -0.546 -0.005 1905.000 -0.405 0.073 1906.000 -0.467 0.086 1907.000 -0.665 0.022 1908.000 -0.804 -0.080 1909.000 -0.795 -0.184 1910.000 -0.731 -0.313 1911.000 -0.712 -0.480 1912.000 -0.696 -0.592 1913.000 -0.589 -0.546 1914.000 -0.434 -0.418 1915.000 -0.358 -0.366 1916.000 -0.382 -0.404 1917.000 -0.375 -0.381 1918.000 -0.225 -0.174 1919.000 0.027 0.151 1920.000 0.232 0.390 1921.000 0.278 0.410 1922.000 0.180 0.244 1923.000 0.055 0.039 1924.000 0.000 -0.071 1925.000 0.001 -0.041 1926.000 -0.007 0.084 1927.000 -0.021 0.234 1928.000 0.044 0.381 1929.000 0.262 0.541 1930.000 0.587 0.712 1931.000 0.868 0.838 1932.000 1.010 0.863 1933.000 1.063 0.798 1934.000 1.135 0.726 1935.000 1.295 0.738 1936.000 1.511 0.837 1937.000 1.653 0.915 1938.000 1.603 0.859 1939.000 1.393 0.691 1940.000 1.167 0.557 1941.000 1.053 0.595 1942.000 1.061 0.794 1943.000 1.102 1.010 1944.000 1.102 1.131 1945.000 1.087 1.148 1946.000 1.116 1.086 1947.000 1.178 0.966 1948.000 1.219 0.825 1949.000 1.215 0.698 1950.000 1.212 0.621 1951.000 1.253 0.619 1952.000 1.278 0.649 1953.000 1.168 0.598 1954.000 0.893 0.421 1955.000 0.578 0.208 1956.000 0.400 0.094 1957.000 0.450 0.139 1958.000 0.668 0.310 1959.000 0.908 0.502 1960.000 1.029 0.576 1961.000 0.967 0.437 1962.000 0.746 0.119 1963.000 0.448 -0.237 1964.000 0.196 -0.482 1965.000 0.107 -0.560 1966.000 0.174 -0.564 1967.000 0.254 -0.632 1968.000 0.242 -0.745 1969.000 0.177 -0.788 1970.000 0.146 -0.762 1971.000 0.190 -0.758 1972.000 0.319 -0.793 1973.000 0.503 -0.841 1974.000 0.664 -0.910 1975.000 0.723 -1.006 1976.000 0.641 -1.093 1977.000 0.465 -1.124 1978.000 0.340 -1.064 1979.000 0.386 -0.918 1980.000 0.564 -0.740 1981.000 0.730 -0.575 1982.000 0.798 -0.434 1983.000 0.776 -0.339 1984.000 0.716 -0.336 1985.000 0.709 -0.415 1986.000 0.869 -0.502 1987.000 1.219 -0.558 1988.000 1.635 -0.605 1989.000 1.920 -0.659 1990.000 1.960 -0.734 1991.000 1.814 -0.856 1992.000 1.653 -0.984 Year Jun-Aug T RingWidth 1881.000 -0.473 0.036 1882.000 -0.522 -0.143 1883.000 -0.572 -0.256 1884.000 -0.597 -0.349 1885.000 -0.548 -0.529 1886.000 -0.443 -0.828 1887.000 -0.353 -1.108 1888.000 -0.324 -1.154 1889.000 -0.364 -0.882 1890.000 -0.448 -0.422 1891.000 -0.483 -0.019 1892.000 -0.386 0.145 1893.000 -0.190 0.059 1894.000 0.017 -0.124 1895.000 0.190 -0.212 1896.000 0.303 -0.142 1897.000 0.311 -0.055 1898.000 0.207 -0.124 1899.000 0.053 -0.296 1900.000 -0.122 -0.376 1901.000 -0.356 -0.336 1902.000 -0.589 -0.303 1903.000 -0.655 -0.344 1904.000 -0.526 -0.445 1905.000 -0.406 -0.563 1906.000 -0.474 -0.609 1907.000 -0.663 -0.520 1908.000 -0.787 -0.362 1909.000 -0.787 -0.253 1910.000 -0.761 -0.233 1911.000 -0.798 -0.254 1912.000 -0.865 -0.212 1913.000 -0.857 -0.032 1914.000 -0.749 0.225 1915.000 -0.617 0.409 1916.000 -0.514 0.435 1917.000 -0.422 0.311 1918.000 -0.291 0.083 1919.000 -0.106 -0.154 1920.000 0.071 -0.256 1921.000 0.146 -0.144 1922.000 0.086 0.090 1923.000 -0.034 0.270 1924.000 -0.095 0.310 1925.000 -0.047 0.265 1926.000 0.076 0.217 1927.000 0.228 0.182 1928.000 0.417 0.148 1929.000 0.675 0.142 1930.000 0.959 0.176 1931.000 1.141 0.194 1932.000 1.171 0.170 1933.000 1.145 0.185 1934.000 1.202 0.353 1935.000 1.393 0.683 1936.000 1.619 1.072 1937.000 1.714 1.386 1938.000 1.604 1.540 1939.000 1.367 1.529 1940.000 1.131 1.428 1941.000 0.951 1.332 1942.000 0.818 1.292 1943.000 0.732 1.296 1944.000 0.716 1.277 1945.000 0.759 1.157 1946.000 0.792 0.921 1947.000 0.747 0.652 1948.000 0.619 0.468 1949.000 0.496 0.438 1950.000 0.491 0.567 1951.000 0.644 0.815 1952.000 0.866 1.081 1953.000 1.002 1.244 1954.000 0.968 1.222 1955.000 0.816 1.024 1956.000 0.696 0.755 1957.000 0.729 0.562 1958.000 0.918 0.488 1959.000 1.129 0.394 1960.000 1.185 0.116 1961.000 1.002 -0.290 1962.000 0.664 -0.520 1963.000 0.329 -0.326 1964.000 0.117 0.187 1965.000 0.076 0.673 1966.000 0.157 0.890 1967.000 0.242 0.840 1968.000 0.290 0.641 1969.000 0.371 0.328 1970.000 0.511 -0.154 1971.000 0.662 -0.770 1972.000 0.790 -1.367 1973.000 0.858 -1.817 1974.000 0.806 -2.035 1975.000 0.617 -1.959 1976.000 0.357 -1.609 1977.000 0.135 -1.114 1978.000 0.061 -0.664 1979.000 0.173 -0.426 1980.000 0.396 -0.399 1981.000 0.611 -0.383 1982.000 0.749 -0.215 1983.000 0.784 0.035 1984.000 0.722 0.156 1985.000 0.639 0.054 1986.000 0.685 -0.195 1987.000 0.957 -0.508 1988.000 1.365 -0.819 1989.000 1.681 -0.952 1990.000 1.742 -0.780 1991.000 1.587 -0.463 1992.000 1.396 -0.290 At 11:56 AM 4/28/00 -0700, you wrote: >Dear Dr. Briffa, > >I am in the process of preparing the opening keynote address for an >international boreal forest carbon cycling conference in Edmonton, Canada, >May 8 - 12. I would like to make reference to your paper in Nature on >reduced sensitivity of recent tree-growth to temperature at high northern >latitudes. > >I have read your paper with great interest when it appeared and have >recently read it again. As you are aware, a community of scientists is >attributing the missing sink to terrestrial ecosystems in the northern >hemisphere, others are arguing that CO2 fertilization, N deposition and >other mechanisms are the cause for increased tree growth in the north. Yet, >neither the forest inventory data and modelling results (see our own work >e.g. Kurz and Apps, 1999, Ecol. Appl. 9: 526-547) nor the data from tree >ring analyses (see your Nature paper) are supporting these hypotheses. > >None of these studies are definitive, and there is clearly room for >alternative interpretations. For example, I appreciate that growth of >individual trees (as studied by dendrochronology) is not a direct indicator >of stand dynamics and therefore net ecosystem production. BUT - 314 studies >across the northern hemisphere should pick up a signal from CO2 >fertilization, N deposition or climate change related changes in the >relationship between temperature and growth rates. If anything, your data >indicate the opposite trend, i.e. that growth was reduced even where >temperature has been increasing. This would argue AGAINST enhanced growth in >the north, not for it. Or am I misinterpreting something? > >The point I would like to make in my presentation is that if these >growth-enhancing processes were at work, then one should see a signal in the >growth rings, yet this does not appear to be the case. I will phrase this as >an observation, not as an argument that there these processes are NOT at >work. > >Three questions for you: > >1. Am I correct in interpreting your results to indicate that growth (at >least at the tree level) has decreased for similar temperatures and that >this is inconsistent with the claims of enhanced tree growth in the north? > >2. Would it be possible to obtain from you the data used to plot the curves >for ALL regions (bottom panel) of Figure 2 in your Nature paper. If yes, I >would very much like to turn it into a figure for my presentation - this is >very difficult to do with the small print in the Nature paper. I would >greatly appreciated it if you could make these data available. I will of >course acknowledge the source in the presentation. > >3. Have you published another paper on the subject that would further >strenghten the arguments? If so, could you please provide the reference so >that I can retrieve the paper. > >Many thanks for your time. > > >Best regards, Werner > > >========================================================= >Werner A. Kurz, Ph.D. >Forestry Team Leader >ESSA Technologies Ltd. >1765 W. 8th Avenue >Vancouver, BC V6J 5C6 >Tel: 604-733-2996 >Fax: 604-733-4657 >e-mail: wkurz@essa.com >www.essa.com > > > > > >