Bristlecone pines were sampled at four sites ranging from the arid lower forest border to the upper treeline in the Snake Range of eastern Nevada. Maximum ring-width response to environmental variation is found at the upper and lower forest limits. Ring-width index series from individual trees, as well as the mean site chronologies, were compared by cross-correlation analysis and principal component analysis, combined with digital filtering to emphasize variations in different frequency ranges. Positive correlation exists between the high-frequency variations at all sites, but the longer term trends and fluctuations at the upper treeline are negatively correlated with fluctuations at the lower altitude sites. Cross-spectral analysis substantiates the results of cross-correlation analysis and indicates that the associated variations in the upper treeline and lower forest border chronologies are concentrated in certain frequency ranges that may have climatic significance. From examination of the climatic response functions, the negatively correlated low frequency variations are tentatively judged to be related to warm- season temperature fluctuations, whereas the positively correlated high frequency variations may be related to precipitation. Frequency-dependent relationships between tree-ring chronologies, or between tree-rings and climate should be considered in the analysis of large arrays of tree-ring

Ring-width variation in trees at upper treeline in the high mountains of temperate latitudes is a potentially important indicator of past climatic variations, especially temperature variations. Bristlecone pines (Pinus longaeva D.K. Bailey and P. aristata Engelm.) were sampled at nine sites in western United States. Plotted annual ring-width indices are given for chronologies that range in length from 532 years in New Mexico, 1409 years in Colorado, and 1239 years in Nevada to 1501 years in eastern California. Possibilities for increasing the length of these chronologies by incorporating tree-ring data from logs and remnants are good in several of the areas, and a 5405-year upper treeline chronology has been developed in California. Tree-ring statistics show that crossdating is poorer, the climatic response is smaller, and the autocorrelation (a measure of year-to-year persistence) is greater in trees at upper treeline sites than at sites near the arid lower forest border. Climatic response functions differ in many details, but generally indicate a positive response of ring growth to warm temperatures in the previous late summer and autumn and current spring and summer. There is a negative response to warm temperatures during some winter and early spring months at several of the sites. The effect of precipitation varies greatly, but a positive response to precipitation during the previous summer or autumn, and during the current spring or summer is indicated. Variations in needle length are related to summer temperature, and may be important in explaining the high autocorrelation of upper treeline ring-width series. Ring-width departures from the long-term mean during the past 500 years were calculated from upper treeline data for 30-year subperiods. The departures are in the same direction over the whole region during many of these subperiods, indicating that climate, rather than local ecological factors, is responsible for the ring-width variations. Comparison of tree-growth fluctuations with meteorological observations at selected stations shows that a general warming trend between the periods 1901-1930 and 1931-1960 is reflected by an upward trend in tree growth. However, low rates of tree growth during an earlier warm period (1850-1869) may be due to a lag in the response of ring -width growth to climatic changes at upper treeline.

A widely spaced grid of tree-ring chronologies most suitable for dendroclimatic analysis of western North America is selected objectively on the basis of 1) numbers in the sample, length in years, and site locations, 2) statistical characteristics of the chronologies, and 3) correlation of chronologies with those on neighboring sites. The chronology statistics are then analyzed to characterize the quality of the selected set. The procedures used in this study are recommended for future climatic analysis to assure objectivity in the selection of quality tree-ring data and to allow comparisons of the statistics for new chronologies to the established data sets.

No description available.

The relationship between archaeology and tree-ring dating, or dendrochronology, is reviewed. Until the past decade, the applications of tree-ring dating to archaeological problems had not been thoroughly exploited. Now, in addition to providing the most precise dating control in the world, dendrochronology is making contributions to behavioral archaeology and to the reconstruction of past environments.

No description available.

The factor analysis of correspondences has been applied to variations as a function of time of the ring widths of the Aleppo pine (Pinus halepensis Mill.) in the French Mediterranean region. This study, involving rings corresponding to 36 years of growth, demonstrates that a general climatic factor (factor 1) intervenes, as well as the constraint of external factors vis-a-vis individual reactions (factor 2). Numerous factors govern ring width. The factor analysis of correspondences enables the demonstration that an important factor is the rain which falls during the vegetation period preceding the summer drought. The importance of the rainfall factor is conditioned by the date at which the average minimum daily temperature exceeds + 4°C, as well as by the distribution of rain during the period in question and by the multiplying effect of the climate of the preceding year. The important effect of unusually low

No description available.

The relations between the width growth of thousand year old larches of the French Maritime Alps (Vallée des Merveilles, north of Nice) and climate are investigated in several ways. A first analysis of tree-ring width compared with meteorological data of the last 21 years (1954-1974) reveals above all an inverse relationship to precipitation and temperature for the months of June and July. Moreover the temperature and rain of the autumn (September in particular) and previous winter seem to affect ring formation as well as the temperature and rain of March and May of the current season. Thus comparison of tree-ring width variations - during the thousand year period of tree growth - with climatic data from various sources (history, chronicle, variations of the glacial front lines, known climatic episodes) shows that climate reconstruction, over several centuries, at the limits of the Mediterranean zone, can be obtained with larch of the French Maritime Alps.

No description available.