Dendrochronology focuses on the relationship between a tree's growth and its environment and thus investigates interdisciplinary questions related to archaeology, climate, ecology, and global climate change. In this study, I examine the growth of two forms of bristlecone pine (Pinus longaeva): strip-bark and whole-bark trees from two subalpine adjacent sites: Patriarch Grove and Sheep Mountain in the White Mountains of California. Classical tree-ring width analysis is utilized to test a hypothesis related to a proposed effect of the strip-bark formation on trees' utilization of atmospheric carbon dioxide. This effect has grown to be controversial because of the dual effect of temperature and carbon dioxide on trees' growth. The proposed effect is hypothesized to have accelerated growth since 1850 that produced wider rings, and the relation of the latter topic to anthropogenic activities and climate change. An interdisciplinary approach is taken by answering a question that relates temperature inferences and precipitation reconstructions from the chronologies developed in the study and other chronologies to Native Americans subsistence settlements and alpine villages in the White Mountains. Strip-bark trees do exhibit an enhanced growth that varies between sites. Strip-bark trees grow faster than whole-bark trees, however, accelerated growth is also evident in whole-bark trees but to a lesser degree. No evidence can be provided on the cause of the accelerated growth from the methods used. In the archaeological study, 88% of the calibrated radiocarbon dates from the alpine villages of the White Mountains cluster around above average precipitation, while no straightforward relationship can be established with temperature variations. These results confirm that water is the essence of life in the desert.

For the first time in northern Scotland, Modern tree-ring chronologies for Scots pine growing on peat are compared against those growing on mineral substrates. Mean tree-ring growth of pine on active bogs/mires is found to be limited to 0.5 to 1 mm yr-1, compared to ≥1.5 mm yr-1 on adjacent mineral sites. Almost instant change of radial growth rates in response to changes in water levels highlights the potential use of pine in reconstructions of lake levels and water tables in bog and mire. Dendroclimatological analysis identifies January and February temperatures to often be more important than summer temperature. Positive correlation of ring-width and North Atlantic Oscillation (NAO) indices also occur in January and February. Lower winter temperatures, due to increased altitude and distance from the moderating effects of the ocean, may be important in limiting tree growth near its northern margin. Moving correlation functions identify a widespread reduction in the response of pine growing on both substrates from the 1920s. Nine subfossil pine site chronologies located beyond the species current northern limit are cross-matched to form a chronology called WRATH-9. This chronology is tentatively crossdated against Irish pine chronologies to provide the first picture of Neolithic Scots pines 200 year expansion from c. 3200 BC and subsequent 250 year retreat across northern Scotland at annual resolution. The mean orientation of maximum radial growth at eleven modern pine sites is found to coincide well with the W/SW prevailing wind, suggesting Scots pine may provide a good proxy indicator of wind. Six coeval Neolithic sites indicate a broadly consistent northerly prevailing wind. This provides tentative evidence for a change of prevailing wind that may be related to a southward incursion of the polar front in the eastern N. Atlantic. The potential of this exciting subfield of dendroclimatological analysis is called dendroaeology and is highlighted for further research.

Radial growth characteristics of a high-elevation shrub species, sea buckthorn (Hippophae rhamnoides), were investigated at four sites in a river valley at altitudes ranging from 3,333 to 3,820 m a.s.l. close to the terminus of the July First Glacier in the western Qilian Mountains of northwestern China. Radial growth of the sea buckthorn was significantly and positively correlated with the mean monthly temperature in June of the current growing season. Based on the fact that fluctuations in the shrub’s radial growth and the glacier’s equilibrium-line altitude (ELA) are affected by climatic variables, a tree-ring width chronology of the four sites was used to reconstruct the ELA from 1950 to 2003. The resulting ELA model explained more than 55.3% of the variance in the ELA of the July First Glacier series. On a decadal time scale, the cumulative-departure curve of the reconstructed ELA series showed an increasing trend from the 1950s to the mid-1960s, followed by a descending trend from the mid-1960s to the mid-1970s. The ELA appears to have remained stable from the mid-1970s to the mid-1990s, but has displayed dramatic variations during the past decade.

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1997 (平成9)年度

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Final Technical Report / Grant No. AFOSR 72-2406 / March 1, 1976 / Results are reported from the first three years of a five-year project to reconstruct past climatic fluctuations in the Northern Hemisphere from variations in the growth rings of trees. The most significant result is the growing international collaboration stimulated by this research effort. The second is the development of 127 high-quality tree-ring chronologies from North America and Europe. Other developments include the establishment of the International Tree-Ring Data Bank, evaluation of multivariate techniques for calibration and analysis, the selection of a revised data set for reconstructing North American climate, and several other technical achievements. These results now will be used to improve reconstructions of past climate and to expand them to eastern North America and Europe.

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Sur la base de constats globaux concernant l’importance d’appliquer des modes de gestion durable des zones forestières et le manque d’investigation concernant l’histoire passée des feux en Europe centrale, il a été entrepris de reconstruire l’histoire des événements de feux et de la dynamique forestière pour des sites d’étude en Allemagne. L’ensemble des données obtenues et analysées ont été utilisées pour l’évaluation du niveau de naturalité des sites étudiés, cette notion étant essentielle pour la mise en place d’une gestion durable, et/ou pour des projets de conservation et / ou de restauration des systèmes perturbés. Concernant les dynamiques des écosystèmes en Europe centrale, il a été souvent mis en évidence que l’homme joue un rôle essentiel depuis des millénaires. Par conséquent, l’approche historique des événements de feux et de la dynamique forestière à été réalisée sur de longues échelles temporelles. Neuf sites d’étude ont été sélectionnés incluant une large gamme de systèmes forestiers d’Europe centrale. Les sites d’études sont répartis dans deux zones générales d’étude : le nord de l’Allemagne (Schleswig-Holstein), qui comprend quatre sites d’étude, et le centre de l’Allemagne (le Harz), qui comprend cinq sites d’étude. Quatre disciplines ont été principalement utilisées. Pour définir l’état actuel des sites d’études ceux-ci ont été caractérisés, utilisant divers indicateurs dendrométriques concernant la structure et la composition des parcelles analysées. Pour obtenir des informations à propos de la dynamique forestière des peuplements forestiers en place des analyses dendroécologiques ont été utilisées. Pour analyser la dynamique forestière sur une longue échelle temporelle, à une échelle spatiale comparable, des analyses pédoanthracologiques ont été menées, combinées à des analyses de sols. De plus, des analyses anthracologiques de séquences de tourbes ont été réalisées, fournissant, combinées avec les données pedoanthracologiques, des enseignements à propos de l’histoire des incendies. L’état actuel et la dynamique forestière récente des sites étudiés indiquent divers niveaux de complexité des peuplements forestiers, correspondant souvent à divers niveaux postulés d’impact anthropique. Il a été obtenu huit chronologies moyennes, standardisées en haute et moyenne fréquences, âgées au maximum de 1744 et au minimum de 1923 ans. A partir de ces chronologies des changements dans les conditions de croissance de peuplements forestiers ont été mises en évidence. Basées sur un ensemble de 71 charbons de bois datés par radiocarbone, il a été mis en évidence, à l’échelle locale et globale, deux principales phases présentant plus d’événements de feux datés, une durant le Pléistocène supérieur/Holocène inférieur, une autre durant l’Holocène supérieur. Pour les deux phases identifiées des forçages climatique et anthropogénique ont été respectivement postulés comme déterminisme des occurrences de feux. Finalement, les différentes données collectées ont été utilisées de façon combinée pour reconstruire l’histoire des feux et des forêts des sites étudiés, afin de contribuer à l’évaluation de leur niveau de naturalité. / Considering two global observations in Central Europe of, firstly, the need for, and development of, sustainable and biological conservation practices for forest and/or woodland areas and, secondly, the lack of long-term fire history, an attempt has been made to reconstruct the fire and the forest history at several investigation sites in Germany. The overall data set gathered and analyzed has been used for on-site naturalness assessment. This latter notion is crucial for forest system conservation/restoration planning, considering the past human impact on forest dynamics. Also, in view of this past human impact on forest systems, which is well-documented for Central Europe, as occurring on a multi-millennium scale, an historical perspective perceptive that combined a long and short temporal scale of investigation was used.Nine investigation sites were selected, in order to include various and representative types of Central European forest. Therefore, the investigation sites were located in two main investigation areas. One is in Northern Germany (Schleswig-Holstein) and includes four investigation sites. The other is in Central Germany (Harz Mountains) and includes five investigation sites. Four main approaches were used. To assess the current state of the investigated site, forest stand characterization was undertaken (i.e. based on various forest attributes that concern stand structure and composition). Tree ring series were analyzed to provide insights about short-term forest tree population dynamics. Then, charcoal records from soil (combined with soil analysis) and peat sequences were qualitatively and quantitatively analyzed. These last two approaches also provide information about the past fire history. Forest current and short-term dynamics illustrated various levels of stand complexity, often corresponding to various levels of human impact that had been postulated. Eight mean site tree-ring chronologies, standardized in high and mid-frequency signal, spanning at a maximum of up to AD 1744 and at a minimum of up to AD 1923, were obtained. The insight, about the identification of events of growing changes and the correlated temporal and, if possible, spatial patterns, was discussed. Charcoal analysis provided a long-term insight about fire history. Based on 71 charcoal radiocarbon dates, it was shown on a macro-scale that there were two phases that had a greater frequency of fire - one during the transition from the late Pleistocene to the early Holocene, and one during the mid- and late Holocene. A strong human control during the most recent fire phase has been postulated. This is supported by on-site soil and peat charcoal record analysis, allowing one to point out the event of environmental changes (disturbances), at local scales. In the end, the on-site data from the various indicators were combined to assess the fire and forest history and the naturalness level of the investigated sites, based on past insights, thereby contributing to a better understanding of the present and helping to anticipate the future.

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