Global Dendroclimatology in Sight from A

780 Nature Vol. 287 30 October 1980 Global dendroclimatology in sight from A. Barrie Pittock Dendroclimatology, the systematic study pressure and that sampling should be con calibration and earlier instrumental and of past climates using tree growth centrated in regions which are historical data for verification, it should be characteristics as proxy climate data, is a climatologically important and/or where possible to produce a detailed and relatively young science. It is often there are gaps in coverage from instru continuous climate reconstruction from confused with the much older and related mental, historical or other proxy data. 1750. Because of the abundance of data for science of dendrochronology, the dating of There is growing confidence that with some calibration and verification, this could specimens by the use of tree-ring modification existing methods can extract prove the best continent-wide proxy sequences. Dendroclimatology has only useful climatic information from trees in climate data set in existence and Europe really developed as a science since the many different parts of the world. could become a test bed for refining 1940s, primarily as a result of the As dendroclimatology has expanded dendroclimatic methods. pioneering efforts of workers at the into new geographical areas over the last Five-hundred-year long chronologies Laboratory of Tree-Ring Research at the decade, techniques have been modified are available already from living conifers in University of Arizona. Elsewhere, the and refined. One example is the use of the Alps and at the northern tree-line and serious application of dendroclimatic density as well as ring-width measurements are expected from living oaks in Scotland, methods has only begun in the last five for climate reconstructions. Density data northern France and south-central years or so. have been used recently to reconstruct Germany. These should allow the It was, therefore, encouraging to find at temperature data in Europe (Schwein reconstructed record to extend back into a recent workshop* attended by 56 gruber et al. Tree-Ring Bulletin 38, 61; the 15th century, and extension back for scientists from 14 countries that 1978). Although basically similar, the 1,000 years at a reduced spatial density is dendroclimatology is making great strides. climate-growth response appears simpler possible (see Serre Tree-Ring Bulletin 38, Greater global coverage was reported in for density than ring width (Parker Syesis 25; 1978). Abundant sub-fossil and contributions from Europe, Asia, South 9, 163; 1976). New techniques take into archaeological material may be used to America, South Africa and Australia, as account that growth in a particular year is extend the chronologies still further. well as eastern North America and the influenced by growth in prior years, that However, the use of such material poses Arctic. A striking departure from early growth is a function of tree age and that the methodological problems in matching research in the semi-arid southwest United climate-growth response may change as series from dead wood with living trees, States was the documentation of useful trees age. A recent innovation has been the especially in a way which will not distort the climatic sensitivity in trees from other than use of selective filter techniques in low-frequency climatic information. Work obviously stressed environments. This was calculating the response and transfer on these problems is being actively pursued particularly well demonstrated for functions. and its importance may be gauged from the Southern Hemisphere rain forest environ Of special interest were plans for potential development of several ments by La Marche and co-workers, for European climate reconstructions put thousand-year chronologies from various the eastern United States by Cook and for forward by one of the global data base parts of the globe including Europe, North Europe by several groups (Schweingruber, working groups. The plans gave high America and New Zealand. The applica Eckstein, Baillie, Pilcher, and see Hughes priority to building up a dense network of tion of densitometric and possibly isotopic et al. 272, 606; 1978; Dunwiddie & chronologies back to at least 1750 covering methods may well overcome some of the La Marche Naturer 286, 796; -1980; the whole of Europe. Using instrumental more serious problems in using these long Garfinkel & Brubaker Nature 286, 872; data from 1880 to the present for tree-ring chronologies. C 1980). Major research groups (outside the western United States) now exist in several in the vicinity of the Sea Foam-house, regions, including the United Kingdom, Nantucket Beach, and the display was continental Europe and the eastern United witnessed by quite a crowd of interested States. Strong interest is also being shown spectators. The Northern Electric Light in China (two workers were present at the Company have erected three wooden towers, meeting), Argentina, Australia and the each 100 feet high, and mounted upon each of Soviet Union. The Chinese plan to use tree these a circular row of twelve electric lights of ring data in regions such as the northwest the Weston patent, each light being estimated 100 years ago at 2,500-candle power. As these towers are but where historical data are not abundant. IT is stated that at the National Exhibition to 500 feet apart and in a triangle, it will be seen Climatologists were also present at the be opened at Milan next year there will be a that the light of 90,000 candles was conference and this led to a stimulating captive balloon, on the model of the one which concentrated within a limited territory. The interaction between the potential users of was so successful in Paris in 1878. It will design of the exhibition was to afford a model dendroclimatic data and the data pro measure not less than 180 feet in of the plan contemplated for lighting cities ducers. It was suggested that attempts circumference, 84 feet in height, and contain from overhead in vast areas, the estimate should be made to reconstruct a wider 15,000 cubic feet of gas. To it will be attached a being that four towers to a square mile of area, range of climatic variables, alongside tem safe and solid car, capable of containing seats each mounting lights aggregating 90,000- perature, precipitation and surface for at least eight persons. A steam-engine is to candle power, will suffice to flood the territory regulate the ascent and descent, and it will rise about with a light almost equal to midday. to a height of about 900 feet, affording a Last evening a motive power of thirty-six A. Barrie Pittock is in the Division of splendid view of Milan and the plains of horses was used in generating the electricity Atmospheric Physics, Commonwealth Lombardy. The balloon will be constructed at from three Western machines, and the lights, Scientific and Industrial Research Milan, m. Henri Beudet, the well-known and with one single flicker, burned steadily and Organization, Australia. experienced aeronaut, having been sent for to brilliantly all the evening. It is difficult to say direct the work. whether the experiment proved anything or •The Second International Workshop on Global Dendrodimatology was held at the Climatic Research Unit, not. The claim put forward by the company is University of East Anglia, July 7-11, 1980. It was sponsored by for an original plan of lighting cities and towns the World Meteorological Organisations, rhc United Nations Enviroment Programme, the Scientific Affairs Division of THE Boston Herald gives the following by grouping and elevating electric lights of any NATO and the US National Science Foundation and was account of an American experiment made on kind." organised by M. K. Hughes (Liverpool Polytechnic), P. M. Kelly (University of Fast Anglia) and J. P. Pilcher (Queen's September 2: - "A novel exhibition of University, Belfast). A report on the proceedings will be powerful electric lights was made last evening From Nature 22, 28 October, 593 & 615, 1880. published in 1980 and a book in I 98 I.