Presented at the Tree-Ring Research Coordination Conference, February 3 and 4, 1961, Tucson.

No description available.

Thesis (Ph. D. - Hydrology and Water Resources)--University of Arizona, 1981. / Includes bibliographical references (leaves 145-149).

The problem of standardizing closed-canopy forest ringwidth series is investigated. A biological model for the tree-ring standardization problem indicated that one class of non-climatic variance frequently responsible for standardization problems could be objectively minimized in theory. This is the variance caused by endogenous stand disturbances which create fluctuations in ringwidth series that are non-synchronous or out-of-phase when viewed across trees in a stand. A time series method based on the autoregressive process is developed which minimizes the timewise influence of endogenous disturbances in detrended ringwidth series. Signal-to-noise ratio (SNR) properties of this method are derived which indicate that autoregressive modelling and prewhitening of detrended ringwidth indices will result in a higher SNR when endogenous disturbances are present in the series. This enables the verification of the SNR theory and the error variance reduction property of the standardization method.

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.

Cores of red spruce (Picea rubens Sarg.) from three upper-elevation sites in Maine, U.S.A., were X-rayed, and minimum and maximum wood densities as well as ring widths were mechanically recorded. The 200- to 300-year series of maximum densities at the three sites show remarkable inter-site similarity. Maximum density and total ring-width series from one site, Elephant Mt., were standardized. Response functions, which measure tree-growth response to climatic variables, were calculated for each of these two series. The ring-width response function explained 66% total variance, of which 34% was explained by climate. The maximum density response function explained 70% total variance, 67% of which was explained by the same climatic variables. Thus, the climate signal from maximum densities is stronger, and perhaps more season-specific, than that of ring widths.

The separating distance over which tree-ring chronologies are significantly correlated is investigated. Any chronology occuring within a radius of 161 km of another is estimated to contain at least half of the common variance occurring at zero separating distance. The separating distance of 161 km is used to calculate the number of nonoverlapping chronology equivalents present within the 40 -, 65 -, and 89-chronology western North American grids. The density of chronologies is calculated for these three grids in various ways. The results give conservative density estimates of five, seven, and eight sites per Mkm² for the three different tree-ring grids.

A general discussion regarding problems inherent to developing climatically sensitive tree-ring chronologies from eastern North America is presented. Tree-ring collections from eastern forests are typically not as climatically sensitive as western collections. Collections have been made from a diversity of sites, but it seems that collections from wet sites or sites of extremely shallow soils may have limited potential. The detrimental effect of crown crowding on sensitivity suggests preference be given to shade-tolerant species and to trees with less crowded crowns exposed in the canopy. Nonclimatic trends in tree-ring data are classified as growth trends and competition trends. Standardization of ring widths removes much of the growth trends, and merging individual tree chronologies into a mean collection chronology eliminates much of the competition trends of individual trees. Separation of ring width into earlywood and latewood widths, where possible, may be quite beneficial for non-pored and diffuse-porous species. However, this procedure seems to be of little value for ring-porous species.

An original procedure and a new mathematical technique have been developed which allowed us to obtain more reliable climatic reconstructions than with prior methods. They have been tested for different sites in Switzerland and Morocco. First, cores that were too short and cores that were not coherent enough with others were excluded, using cross-spectral analysis. Second, detrending and master chronologies were calculated. Three methods were compared: polynomial, high-pass filter, and spline indexing. An optimal detrending was obtained through comparison with climate, but there seems to be no general rule for it. More reliable and longer climatic reconstructions are made possible. A response functions technique in three steps is presented: regression after extracting principal components on monthly climatic parameters, on seasonal parameters, and on more biological parameters such as potential evapotranspiration, multiple spectral regression introducing frequency domain. This procedure provides a more complete and more dynamic view of tree growth. The transfer function method and its verification are illustrated for different sites in Morocco: three climatic parameters in Tetouan (February, May, and June temperatures) and one in Marrakech (May temperature) have been successfully reconstructed. These reconstructions are confirmed by different verifications.