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Dendrochronology (from , ''dendron'', "tree limb"; , ''khronos'', "time"; and , ''-logia''), or tree-ring dating, is the scientific method of dating based on the analysis of patterns of ''tree rings'', also known as ''growth rings''. Dendrochronology can date the time at which tree rings were formed, in many types of wood, to the exact calendar year. This has three main areas of application: paleoecology, where it is used to determine certain aspects of past ecologies (most prominently climate); archaeology and the history of art and architecture, where it is used to date old panel paintings on wood, buildings, etc.; and radiocarbon dating, where it is used to calibrate radiocarbon ages (see below). In some areas of the world, it is possible to date wood back a few thousand years, or even many thousands. As of 2013, fully anchored chronologies in the northern hemisphere extend back 13,900 years. ==History== The Greek botanist Theophrastus (ca. 371 – ca. 287 BC) first mentioned that the wood of trees has rings.〔Theophrastus with Arthur Hort, trans., ''Enquiry into Plants'', volume 1 (London, England: William Heinemann, 1916), Book V, (p. 423. ) From p. 423: "Moreover, the wood of the silver-fir has many layers, like an onion; there is always another beneath that which is visible, and the wood is composed of such layers throughout." Although many sources claim that Theophrastus recognized that trees form growth rings annually, this is not true.〕〔For the history of dendrochronology, see: * R. A. Studhalter (April 1956) "Early history of crossdating", ''Tree-Ring Bulletin'', 21 : 31–35. Available on-line at: (University of Arizona ) (Condensed from: Studhalter, R. A. (1955) "Tree growth: some historical chapters", ''Botanical Review'', 21 : 1–72.) * Studhalter, R. A. ; Glock, W. S. & Aoerter, S. R. (1963) "Tree growth, some historical chapters in the study of diameter growth", ''Botanical Review'', 39 (3) : 245–343. * James H. Speer, ''Fundamentals of Tree-ring Research'' (Tucson, Arizona: University of Arizona Press, 2010), Chapter 3: History of Dendrochronology, pp. 28–42.〕 In his ''Trattato della Pittura'' (Treatise on Painting), Leonardo da Vinci was the first person to mention that trees form rings annually and that their thickness is determined by the conditions under which they grew.〔See: * Leonardo da Vinci, ''Trattato della Pittura'' ... (Rome, (Italy): 1817), (p. 396. ) From p. 396: ''"Li circuli delli rami degli alberi segati mostrano il numero delli suoi anni, e quali furono più umidi o più secchi la maggiore o minore loro grossezza."'' (The rings around the branches of trees that have been sawn show the number of its years and which () were the wetter or drier (to ) the more or less their thickness.) * Sarton, George (1954) "Queries and Answers: Query 145. — When was tree-ring analysis discovered?", ''Isis'', 45 (4): 383–384. Sarton also cites a diary of the French writer Michel de Montaigne, who in 1581 was touring Italy, where he encountered a carpenter who explained that trees form a new ring each year.〕 In 1737, French investigators Henri-Louis Duhamel du Monceau and Georges-Louis Leclerc de Buffon examined the effect of growing conditions on the shape of tree rings.〔du Hamel & de Buffon (27 February 1737) (''"De la cause de l'excentricité des couches ligneuses qu'on apperçoit quand on coupe horisontalement le tronc d'un arbre ; de l'inégalité d'épaisseur, & de different nombre de ces couches, tant dans le bois formé que dans l'aubier"'' ) (On the cause of the eccentricity of the woody layers that one sees when one horizontally cuts the trunk of a tree ; on the unequal thickness, and on the different number of layers in the mature wood as well as in the sapwood), ''Mémoires de l'Académie royale des science'', in: ''Histoire de l'Académie royale des sciences'' ..., pp. 121–134.〕 They found that in 1709, a severe winter produced a distinctly dark tree ring, which served as a reference for subsequent European naturalists.〔du Hamel & de Buffon (4 May 1737) ("Observations des différents effets que produisent sur les végétaux les grandes gelées d'hiver et les petites gelées du printemps" ) (Observations on the different effects that the severe frosts of winter and the minor frosts of spring produce on plants), ''Mémoires de l'Académie royale des science'', in: ''Histoire de l'Académie royale des sciences'' ..., pp. 273–298. Studhalter (1956), p. 33, stated that Carl Linnaeus (1745, 1751) in Sweden, Friedrich August Ludwig von Burgsdorf (1783) in Germany, and Alphonse de Candolle (1839–1840) in France subsequently observed the same tree ring in their samples.〕 In the U.S., Alexander Catlin Twining (1801–1884) suggested in 1833 that patterns among tree rings could be used to synchronize the dendrochronologies of various trees and thereby to reconstruct past climates across entire regions.〔Alexander C. Twining (1833) ("On the growth of timber — Extract of a letter from Mr. Alexander C. Twining, to the Editor, dated Albany, April 9, 1833" ), ''The American Journal of Science'', 24 : 391–393.〕 The English polymath Charles Babbage proposed using dendrochronology to date the remains of trees in peat bogs or even in geological strata (1835, 1838).〔See: * (Anon.) (1835) ("Evening meeting at the Rotunda" ), ''Proceedings of the Fifth Meeting of the British Association for the Advancement of Science held in Dublin during the week from the 10th to the 15th of August, 1835, inclusive'', pp. 116–117. * Charles Babbage (1838) ("On the age of strata, as inferred from rings of trees embedded in them" ), ''The Ninth Bridgewater Treatise: A Fragment'', 2nd ed. (London, England: John Murray, 1838), pp. 256–264.〕 During the latter half of the nineteenth century, the scientific study of tree rings and the application of dendrochronology began. In 1859, the German-American Jacob Kuechler (1823–1893) used crossdating to examine oaks (''Quercus stellata'') in order to study the record of climate in western Texas.〔See: * Jacob Kuechler ( August 6, 1859) "Das Klima von Texas" (The climate of Texas), ''Texas Staats-Zeitung'' (state newspaper ) (San Antonio, Texas), p. 2. * "The droughts of western Texas", ''The Texas Almanac for 1861'', pp. 136–137 ; see (especially p. 137. )〕 In 1866, the German botanist, entomologist, and forester Julius Ratzeburg (1801–1871) observed the effects on tree rings of defoliation caused by insect infestations.〔J. T. C. Ratzeburg, ''Die Waldverderbniss oder dauernder Schade, welcher durch Insektenfrass, Schälen, Schlagen und Verbeissen an lebenenden Waldbäumen entsteht.'' (deterioration of forests or lasting damage that arises from feeding by insects, debarking, felling, and gnawing on living forest trees. ), vol. 1, (Berlin, (Germany): Nicolaische Verlag, 1866), (p. 10. ) From p. 10: ''"Die beiden, auf Taf. 42, Fig. 6 (mit dem Durchschnitt Fig. 7) und Fig. 1 (mit dem Durchschnitt Fig. 2) dargestellten Zweige hatten in dem Frassjahre 1862 einen doppelt so starken Jahrring als in dem vorhergehenden angelegt, und auch der (hier nicht abgebildete) Ring des jährigen Triebes war bei den gefressenen stärker as der eines nicht gefressenen."'' (Both branches that are presented in plate 42, fig. 6 (with the cross-section in fig. 7) and fig. 1 (with the cross-section in fig. 2) had produced, in the defoliation year of 1862, a growth ring that was twice as strong as in the preceding one, and so was the ring of the year-old shoot (not illustrated here) stronger in the case of the defoliated tree than one that was not defoliated.)〕 By 1882, this observation was already appearing in forestry textbooks.〔Franklin Benjamin Hough, ''The Elements of Forestry'' (Cincinnati, Ohio: Robert Clarke and Co., 1882), (pp. 69–70. )〕 In the 1870s, the Dutch astronomer Jacobus C. Kapteyn (1851–1922) was using crossdating to reconstruct the climates of Holland and Germany.〔Kapteyn, J. C. (1914) ("Tree-growth and meteorological factors" ), ''Recueil des Travaux Botaniques Néerlandais'', 11 : 70–93.〕 In 1881, the Swiss-Austrian forester Arthur von Seckendorff-Gudent (1845–1886) was using crossdating.〔See: * Seckendorff, Arthur von (1881) "Beiträge zur Kenntnis der Schwarzföhre ''Pinus austriaca'' Höss" (to our knowledge of the black pine ''Pinus austriaca'' Höss ), ''Mitteilung aus dem forstlichen Versuchswesen Oesterreichs'' (from the Austrian Department of Forestry Research ) (Vienna, Austria: Carl Gerold Verlag, 1881), 66 pages. * Speer (2010), p. 36.〕 From 1869 to 1901, Robert Hartig (1839–1901), a German professor of forest pathology, wrote a series of papers on the anatomy and ecology of tree rings.〔Speer (2010), p. 36–37.〕 In 1892, the Russian physicist Fedor Nikiforovich Shvedov (Фёдор Никифорович Шведов) (1841–1905) wrote that he had used patterns found in tree rings to predict droughts in 1882 and 1891.〔See: * Шведов, Ф. (Shvedov, F.) (1892) "Дерево, как летопись засух" (The tree as a record of drought), ''Метеорологический Вестник'' (Meteorological Herald), (5) : 163–178. * Speer (2010), p. 37.〕 During the first half of the 20th century, the astronomer A. E. Douglass founded the Laboratory of Tree-Ring Research at the University of Arizona. Douglass sought to better understand cycles of sunspot activity and reasoned that changes in solar activity would affect climate patterns on earth, which would subsequently be recorded by tree-ring growth patterns (''i.e.'', sunspots → climate → tree rings). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dendrochronology」の詳細全文を読む スポンサード リンク
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