Dendrochronology

Balkenprobe aus dem Rathaus von Gödenroth (Eichenholz)
bar sample from the city hall of Gödenroth (oakwood)

the dendrochronology (griech. dendron = tree, chronos = time) is a dating method of the archaeology, which art science and the Dendroökologie, with which the Jahresringe are counted by trees. The term dendrochronology goes on the American Astronomer Andrew Ellicott Douglas (1867-1962) back.

To table of contents


history of the dendrochronology

of Jahresringe of years with good growth conditions are broader than such from years with bad living conditions. Since for all trees of a kind in a certain area the living conditions are approximately alike, thus all trees point to oneKind of this region the same characteristic sample of narrow and broad Jahresringen up.

Already Leonardo da Vinci assumed that the Jahresringe of trees reflect the climatic growth circumstances. End 19. Century is to have already determined Arthur baron von Seckendorff Gudent the age of trees by means of Jahresringen.

The founder of the dendrochronology, Andrew E. , Cycle of the sunspots wanted to point Douglases out on the basis the Jahresringe a connection between the earth climate and the 11jährigen. Douglases drilled as first trees, in order to receive by means of the thickness of the Jahresringe of the received drill cores information about the climatic growth conditions.Completely this is unproblematic however not, since still different factors play a role with the increase of the trees, like e.g. the nutrient supply, the competition of neighbour trees, damages, diseases and Schädlingsbefall. Thus a recognized proof of the connection of sunspot activities and tree ring thickness never succeeded to it.

Douglases measuredthe thickness of the Jahresringe of long-lived trees and registered the values into a diagram. It provided a data collection, by it the characteristic successions of extremely narrow and broad Jahresringen (so mentioned event years or event years) of differently old, but itself temporally overlapping trees upto the coincide set to a time scale. By means of these „lap technology “(Crossdating method) could determine Douglases also the age of died and blocked tree samples. In the year 1929 to it thereby the list succeeded 1229 years is enough for year ring chronology continuously from the present in the year the 700 n. Chr. goes back.Over this chronology it could date indianischer dwellings, when it registered the yearly ring samples of the archaeological find woods into the older section of its chronology.

expiration of the analyses

by the overlay of the ring samples of many trees (Crossdating method) develops an averaged tree ring succession (year ring chronology), due to thatoverlapping lifetimes of the trees many thousands of years to take off knows. Up to the introduction of the electronic data processing in the middle 20. Century was the determination of contemporaneous growth sections of different trees and the production of the resulting year ring chronologies a time-consuming affair. The samples (tree disks or drill cores) were smoothed and with oneContrast means (z. B. Chalk) prepares. Subsequently, one measured each individual year ring with the magnifying glass. The entire measured values were drawn as time series on Transparentfolie. The time series of all measured trees were finally shifted annually against each other on the Leuchttisch and examined on optical agreement. A characteristic measurethe agreement was the Gleichläufigkeitswert (that is the percentage of the curve intervals in the lap range of two curves, which rise synchronously or fall). In the resulting year ring chronology the common growth samples of the trees step out more strongly, while the individual samples are suppressed. Intervals, in those a high percentage thatif single trees took part the same tendency (rise or traps) exhibited, wise intervals were called, to which with further comparisons a high meaning came. With increasing availability of the electronic data processing one provides these comparisons virtually in the computer, whereby in the meantime also numerous statistic parameters of the time series analysis (for instance the coefficient of correlation) to be raised.

Such year ring chronologies serve as reference samples for the further dating of tree samples of an area. If a year ring chronology exhibits gaps to the present, then only a relative dating is possible (z. B. Tree A became x years in former times as a tree B pleases). A year ring chronology is however enoughby the past completely into the present, then the Jahresringe of a tree sample for this period can be dated absolutely and year-exactly. A tree sample is undatierbar, if it z. B. no area and/or. a year ring chronology to be assigned cannot or if it from to few Jahresringen(less than approx. 80) exists.

important yearly ring tables

in some areas could be provided in such a way for some tree species relatively complete yearly ring tables for the last 10,000 years (e.g. The Central European oak chronology). An error free dendrochronology makes it possible to assign to each tree ring the year its emergence.

Extentthe provided curves:

  • Hohenheimer year ring calendar (2004) completely to 10,461 v. Chr., younger Dryas
  • ostmediterrane curve (Aegean Dendrochronology Project) to 1,800 v. Chr., Bronzezeit (conditions 2003)
  • Belfast (Ireland) 5,474 v. Chr. (2006)
  • English standard curve to 5,012 v. Chr. (2006)
  • Bristlecone Pines chronology
  • Sequoiadendron giganteum chronology

for further informationsee article yearly ring tables.

the dendrochronology reached

sample applications of the dendrochronology spectacular one of successes in the meantime when investigations to the latemedieval board painting. The analyses of the oak boards, on which about Hieronymus Bosch tended to paint, led to the clear result that a whole set from so farBosch attributed works from the Gesamtœuvre to be separated had. The boards came from trees, which partially only decades pleases after Boschs death was.

Dendrochronologisch could also for one approx. ten-year period around the year 540 n. Chr. a climatic disaster to be occupied (see also Plague under Justinian I., the so-called. Justiniani troubles, and Michael of the Syrians). As a cause of this world-wide atmospheric turbidity comet impacts or volcanic eruptions are assumed.

Also to the temporal classification of the wood used with the building of music instruments (caper, pulling and key instruments) the dendrochronology is used.Apart from exact dating with well-known manufacture places the method in the reversal knows also referring to the origin of the wood and the wood use in different workshops, like e.g. Jakobus Stainer to that of the master of building of playing the violin, give.

dendrochronology in the natural science

the dendrochronology goesin the natural science the far over function of a pure instrument for the age regulation of wood outside. So climatic growth correlations can be deduced for the modern times also on the basis the linkage of climatic data with the year ring chronologies, which document the reaction of the trees to environmental influences in a yearly dissolution. A task range of theseAdjustment of the dendrochronology consists of it supplying prognoses for the growth of trees and thus for the ecological system forest with changing climate conditions (climatic change). There the individual growth of trees however apart from the climatic influences of many other factors like e.g. Age trend, anthropogenen influences,Competition, autocorrelation, noise etc. , this depends so must be out-counted only. But the dendrochronology avails itself of an extensive equipment at mathematical methods.

Before the time of the scientific weather measurements (starting from 1850), from which hardly reliable data is available, becomes the dendrochronology as indirect climatic archivesconsulted.

An addition of the dendrochronology is the Dendroanalytik, which the identification and quantification of materials like e.g. Makes possible for heavy metals in the year rings.

argument with sceptical social groups

the dendrochronology becomes partial something similar of different social groups from different motives, but withArguments attacked. Public attention here in particular boy earth creationists achieve and, particularly in the German-speaking countries, publications from the surrounding field of the so-called chronology criticism.

Often used point of attack e.g. is. the mutual reference between dendrochronology and radio carbon dating, which from view of the representatives of these groups to a mutual calibrationthe two methods lead. In order to examine and calibrate radio carbon dating more exact, in the start time (over 1950) the dendrochronology was consulted, which was at this time even still in a relatively early level of development and only could make available few American time series. Therefore and due to further,presupposed basic assumptions within these groups it is discussed whether it can have come both with the one and with the other method to discrepancies, which could not have added themselves and provide in such a way in both regulation methods for insignificant errors.

Dendrochronologen and representatives of the radio carbon methods pointwhereupon that already before development of the radio carbon method with the structure of safe year-rope-that-old dendrochronologies one began for example using in 19. and early 20. Century and up to over three thousand years old giant giant trees [1] gefällten in great quantities. Besides is today a multiplicity ofindependent examinations of the conditions of both methods possible (measurements of sediment samples, Korallen, ice drill cores, Stalagmiten). Thus the danger is one of these groups subordinated to “circular letters” proceeding impossible, why these and other comparable statements from the range of these groups are scientifically unrelevant rejected usually than.

see also

literature

to the method

  • M. G. L. Baillie: A Slice through Time. Dendrochronology and precision Dating. London 1995, ISBN 0-7134-7654-0
  • Fritz H. Schweingruber: The year ring. Location, methodology, time and climate in thatDendrochronology. Berne and Stuttgart 1983, ISBN 3-258-03120-7

extension of the curves

  • fall W. Manning, Bernd Kromer, Peter Ian Kuniholm, Maryanne W. Newton: Confirmation OF near absolute dating OF east Mediterranean bronze Iron Dendrochronology. Antiquity of 77, 2003

sample applications

  • Mike Baillie: Exoduston Arthur. Catastrophic Encounters with Comets. London 1999, ISBN 0-7134-8352-0
  • Peter Klein: Dendrochronological analysis OF Works by Hieronymus Bosch and his Followers. In: Jos Koldeweij/Bernard Vermet (Hrsg.): Hieronymus Bosch. New Insights Into His would run and Work, NAi Publishers, Rotterdam o.J. (2001), ISBN 90-5662-214-5
  • Micha Beuting: Holzkundliche and dendrochronologische investigations at resonance wood as contribution to the Organologie. Boiler publishing house, Remagen Oberwinter 2003, ISBN 39-3563-8485
  • Micha Beuting, Peter Klein: Dendrochronologi investigations at caper instruments of Jacob Stainer. In: Seipel, W. (Hrsg.): Jacob Stainer: … kayserlicher servant and more geigenmacher to Absom.Exhibition catalog of the art-historical museum Vienna, Milan: Skira, S. 167-171, ISBN 3-85497-060-9

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