Fritts, Harold C.; Xiangding, Wu (Tree-Ring Society, 1986)
Three different response-function programs are applied to three tree-ring chronologies, two of Pinus ponderosa Laws. and one of Juniperus occidentalis Hook. These data were analyzed before and after ARMA modeling was applied. The results are described and compared to one another as well as to those obtained from all-steps multiple regression, stepwise multiple regression, ridge regression, and simple correlation. In spite of methodological differences all multivariate methodsproduced remarkably similar results. The results from simple correlation differed the most. Some differences among the response functions were apparent, especially in the coefficients associated with prior growth. The response-function results have smaller error estimates than ridge regression. According to Cropper (1985) this error in the response-function results is underestimated by approximately 40 %. The rationale for the different response-function solutions is discussed.
Villalba R.; Boninsegna, Jose A.; Holmes, Richard L. (Tree-Ring Society, 1985)
Dendrochronological problems in dating tropical tree species are responsible for a large gap in global dendroclimatic reconstructions. Study of Cedrela and Juglans in the low-latitude forests of northern Argentina and Bolivia has resulted in development of four chronologies. These genera have good tree-ring characteristics, and statistics indicate that they have good potential for dendroclimatology. Longer series should be obtained from older stands.
Boninsegna, José A.; Holmes, Richard L. (Tree-Ring Society, 1985)
The longest tree-ring chronologies for the Southern Hemisphere published to date go back to A.D. 1011 in central Chile; 1028 in Tasmania, Australia; 1140 in western Argentina; and 1256 on the North Island, New Zealand. For paleoclimatic and other studies longer time series would be very desirable. Here we report on the first successful crossdating and chronology development for Fitzroya cupressoides, a redwood-like conifer in western Argentina, which goes back to 441 and exhibits desirable statistical characteristics.
Bhattacharyya, Amalava; LaMarche, Valmore C., Jr.; Telewski, Frank W. (Tree-Ring Society, 1988)
Tree-ring samples were collected from six coniferous species in the western Himalayan ranges during the summer of 1984 in order to evaluate their potential for use in dendroclimatic reconstructions. Picea, Abies, and Pinus spp. had previously been collected for ring widths and densitometric analysis by Hughes and co-workers on relatively mesic subalpine sites near the Vale of Kashmir. Our results support this earlier work in that ring-width series from these habitats are relatively complacent and contain little dendroclimatic information. Density and ring widths are largely temperature-dependent. However, our sampling included Cedrus deodara and Pinus gerardiana from lower altitudes in the dry inner valleys of the Pir Panjal Range, south of Kashmir. Both species exhibit great age, high mean sensitivity and good intra- and inter-specific crossdating, and yielded chronology statistics suggestive of a drought response. We strongly recommend that they receive high priority in future tree-ring research in northwest India.
I propose an approach to provide 95% confidence intervals for a chronology of low-frequency tree-ring variation so that a level of significance or importance for trends can be inferred. The approach also visually reveals the portions of a chronology in which sample depth is so poor that low-frequency variation is not robustly estimated. A key characteristic of the approach is that it is essentially a reordering of the individual steps commonly used in constructing standard tree-ring chronologies; consequently, it is computationally simple for researchers who already routinely construct standard tree-ring chronologies. The most important ramification of the approach is that each year of the chronology has a distribution of smoothed index values with which to estimate confidence intervals around the chronology of low-frequency variation. It can be argued that the approach constitutes multiple significance testing of means, which causes the α level for the confidence interval to be unknown. Nonetheless, the approach is still useful in that it provides a way to evaluate the probable importance of low-frequency trends expressed in tree-ring chronologies.
This article describes the analysis of tree-ring collections from standing trees of sixteen species at twenty sites distributed throughout the Italian Peninsula. Visual and numerical crossdating among ring widths allowed the computation of standard and residual tree-ring chronologies. Relationships among chronologies were identified by Spearman's coefficient of rank correlation, using Bonferroni's inequality to adjust significance level. The oldest living tree sampled to date is a 963-year old palebark pine (Pinus leucodermis Ant.) at Parco del Pollino. Individuals more than two centuries old were identified at eleven sites for eight species. The tree-ring network so far consists of twenty-two chronologies for nine species at nineteen sites. Seven conifer species account for ten chronologies and two angiosperm species account for the remaining twelve chronologies. The most represented species is Fagus sylvatica L., with eleven chronologies distributed over the entire peninsula and highly correlated with one another. The order of autoregressive models fitted to the data never exceeded two. In particular, the order of autoregressive models fitted to Fagus sylvatica chronologies decreased with decreasing age of sampled trees. Based on the significant coefficients of rank correlation, residual chronologies of Fagus sylvatica could be separated into northern, central, and southern groups. This points to the existence of broad regions distributed along a latitudinal gradient, corresponding to large-scale climatic regimes over the Italian Peninsula.
Fairchild-Parks, James A.; Harlan, Thomas P. (Tree-Ring Society, 1992)
Tree-ring dating was used to develop construction scenarios for two log structures, the Draper and the Fuller buildings. in the Edwards Plateau region of Texas. The Draper building was constructed in 1902-3, and added onto in 1906. The dating of the Fuller building is less certain, but the structure probably was built in the 1860s or 1870s.
Huante, Pilar; Rincón, Emmanuel; Swetnam, Thomas W. (Tree-Ring Society, 1991)
An exploratory investigation of tree growth and climate relationships in Abies religiosa from Michoacan, Mexico, produced the first crossdated and standardized tree-ring chronology from the North American tropics. Pearson correlation coefficients and principal components response function analysis were employed. Results indicate that ring-width series from this species have moderately high signal-to-noise ratio (S/N = 13.42). A substantial percentage of the ring-width signal can be explained by instrumented monthly climate data, particularly spring precipitation and winter temperature. Although correlation between climate data and the tree-ring measurements indicate that growth of Abies religiosa is highly influenced by year-to-year climate variation, longer climate records and tree-ring chronologies are needed from this tropical region to improve understanding of climate -tree growth relationships, and for dendroclimatic reconstruction.
Brown, Peter M.; Hughes, Malcolm K.; Baisan, Christopher H.; Swetnam, Thomas W.; Caprio, Anthony C. (Tree-Ring Society, 1992)
Giant sequoia was one of the first species that A. E. Douglass examined in his pioneering tree- ring research. Recent attention to sequoia, stimulated by fire history studies in sequoia groves, has resulted in new ring-width chronologies based on both recently collected tree-ring material and Douglass' original samples. The development and characteristics of four new multimillennial sequoia chronologies are described here. Three of these chronologies are based on tree-ring series from individual sites: Camp Six (347 B.C. to A.D. 1989), Mountain Home (1094 B.C. to A.D. 1989), and Giant Forest (1235 B.C. to A.D. 1988). The fourth is a composite chronology (1235 B.C. to A.D. 1989) that includes radii from the other three chronologies. Sequoia ring series are generally complacent with occasional narrow rings ("signature years"). Ring-width standardization was complicated by growth releases, many of which are known to have been caused by fires. Such growth releases confuse climatic interpretation of low-frequency signals in the time series. Ring- width series were detrended with cubic splines with 50% frequency response function at 40 years to de-emphasize low-frequency variation and were fit with autoregressive time series models to remove persistence. The resulting prewhitened chronologies contain primarily a high frequency climate signal and are useful for assessing the past occurrence of extreme drought events and for dating applications. The dating chronology originally developed by Douglass is confirmed and the annual nature of giant sequoia tree rings unequivocally verified.
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