Analysis of the relationship between ring-width indices of pedunculate oaks (Quercus robur L.) in the Niepotomice Forest with average monthly air temperatures (1826-1980) and total monthly precipitation (1881-1985) in Cracow revealed a strict relationship between tree -growth and the precipitation of June-July, May-July, and June-August. These relationships are described by a high percentage of agreement, at or around 70 %, and coefficients of correlation (rx) of 0.40 (June-July), 0.36 (May-July) and 0.30 (June-August). The group of 10 oaks with the highest coefficients between growth and precipitation yielded still higher correlations: 0.50, 0.50, and 0.41, respectively. High total monthly precipitation in June and July favors radial growth, while low precipitation reduces radial growth. The influence of air temperature on oak ring-width indices is less significant. The highest positive correlation occurs for January to April of the preceding year. Correlations for the years of radial growth have values close to or below (June) zero except for August.

The signal strength of a biweight site chronology is properly viewed as an outcome of analysis rather than as a property of the forest-climate system. It can be estimated by the evenness of the empirical weights that are assigned to individual trees. The approach is demonstrated for a 45-year biweight chronology obtained from 40 jack pine (Pinus banksiana Lamb.) trees. The annual evenness of the empirical weights is calculated by indices derived from the Shannon and Simpson diversity indices, and the variances are found by the jackknife procedure. The annual estimates are then averaged to find an overall estimate of biweight signal strength for the 45-year period. These techniques are most useful for determining sample sizes for the biweight procedure, and for comparing different methods of detrending and standardizing data sets prior to applying the biweight mean-value function.

Special sanding films (400 grit to 23 micron) and fine sandpapers (1200-1500 grit) can be used to surface increment cores containing narrow rings (e.g., >50 rings per cm) so that rings are clearly visible for microscopy and photography.

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.

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.

Hypotheses about the causes of the growth and decline of the Chacoan regional interaction system in the southwestern United States between A.D. 900 and 1200 are evaluated against tree-ring evidence and the results of an empirical model (PRECON) that computes the statistical relationships between climate and ring-width indices during the 20th century and applies the results to hypothesized precipitation or temperature changes. The statistical responses of 23 indexed conifer ring-width chronologies from New Mexico and Colorado to variations in monthly temperature and precipitation were calculated. Simulated decreases in prior autumn-winter precipitation markedly reduced ring widths, while decreased current summer precipitation was less effective, sometimes reducing ring width or having little effect. Decreased prior winter temperature slightly reduced ring width, while decreased growing season temperature usually increased or did not effect ring widths. Evaluated in terms of these results, the Chaco Canyon area tree-ring record (1) indicates that favorable climatic conditions in the 10th, 11th, and early 12th centuries fostered the growth of the Chacoan system, (2) shows that dry autumn-winter and summer conditions in the middle 1100s contributed to the downfall of the system, (3) does not support the proposition that centuries-long climatic fluctuations evident in southwestern Colorado affected Chaco Canyon, (4) does not support the idea of shifts from summer-to winter-dominant precipitation regimes, and (5) contributes little to assessing the role of anthropogenic environmental change in the collapse of the Chacoan system.

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.

During the past 100 years, researchers have investigated the potential of hundreds of tree and shrub species for use in applications of tree-ring research. Although several lists of species known to crossdate have been published, investigated species that do not crossdate are rarely included despite the usefulness of this information for future research. This paper provides a list of the Latin and common names of 573 species that have been investigated in tree-ring research, information on species known to crossdate, and information on species with measurement and/or chronology data in the International Tree-Ring Data Bank. In addition, a measure of the suitability of a species for future tree-ring applications, the Crossdating Index (CDI), is developed and proposed for standard usage.

Phipps showed that the cross-sectional area of successive tree rings in suppressed red maples and chestnut oaks, sampled at three-foot intervals above the base, is approximately constant. I show that this invariance in cross-sectional area is consistent with ring width varying as the inverse square root of ring number and with mean ring diameter and trunk diameter each scaling as the square root of ring number. These results may be useful in formulating growth rules for tree trunks of selected species, under constant environmental conditions, in terms of a single independent variable. For example, if elastic similarity holds, trunk height is proportional to the two-thirds power of trunk diameter. This relation implies that trunk height scales as the cube root of ring number. Thus, trunk height and trunk diameter may, in principle, both be expressed in terms of one independent variable, ring number.

O padrão espacial das árvores em uma floresta é influenciado por variáveis abióticas e bióticas. Entre as principais variáveis abióticas estão o relevo, a disponibilidade de luz, nutrientes e água, e a caracterização do solo. Entre as principais variáveis bióticas estão os processos dependentes da densidade, tais como a competição intraespecífica e interespecífica, a herbivoria, a ocorrência de doenças, a fenologia e dispersão de sementes. Desse modo, investigar o padrão espacial das árvores, segundo suas classes de tamanho, e segundo suas espécies mais abundantes, pode fornecer evidências sobre a estrutura da comunidade vegetal. A descrição do padrão espacial das árvores e das espécies mais abundantes em diferentes formações florestais foi realizada usando ferramentas estatésticas mais apropriadas para investigar mapas das árvores. A Função K de Ripley tem como principais vantagens a possibilidade de detectar o padrão espacial em diversas escalas de distâncias simultaneamente, e avaliar a dependência espacial entre grupos de árvores. Os padrões observados foram comparados com os modelos de Completa Aleatoriedade Espacial, para a função univariada, e de Completa Independência Espacial, para a função bivariada. Diferentes formações florestais, típicas da região sudeste do Brasil, foram comparadas neste estudo: Floresta Ombrófila Densa Submontana, Savana Florestada (Cerradão), Floresta Estacional Semidecidual e Formação Pioneira com Influência Marinha (Restinga). Esta dissertação de mestrado integra o Projeto "Diversidade, dinâmica e conservação em florestas do Estado de São Paulo: 40 ha de parcelas permanentes", do Programa Biota da FAPESP. Neste projeto, uma parcela de 10,24 ha foi montada em cada formação florestal, e todas as árvores com circunferência na altura do peito a partir de 15 cm foram medidas, mapeadas e identificadas. Os resultados obtidos neste estudo ressaltam o caráter agregado em florestas tropicais, uma vez que o padrão agregado foi observado em todas as florestas estudadas. As árvores do Cerradão e da Restinga apresentaram padrões muito próximos, com uma agregação definida até uma certa escala de distâncias. Para a Floresta Ombrófila, o padrão agregado foi significativo em toda a escala de distâncias. Na Floresta Estacional, tendência à aleatoriedade foi observada, embora uma agregação significativa tenha sido notada para curtas distâncias. A análise do padrão espacial segundo classes de tamanho mostrou que as primeiras classes possuem, em geral, padrões agregados significativos, enquanto para as classes seguintes o padrão aleatório foi predominante. Em linhas gerais, o padrão espacial das espécies acompanhou o padrão geral de cada formação florestal. O padrão das espécies dominantes é sempre muito semelhante ao padrão espacial da floresta como um todo. Como era esperado, as espécies dominantes desempenham importante papel na ocupação do espaço horizontal em tais florestas, contribuindo de modo decisivo para a caracterização do padrão espacial da comunidade. Espécies que ocorreram em diferentes florestas apresentaram pequenas diferenças no seu padrão espacial, ressaltando-se assim a importância da sua autoecologia e dos processos ecológicos intrínsecos a cada comunidade. / Tree spatial patterns are influenced by abiotic and biotic environment. Among the main abiotic factors are topography, light, nutrients, soil and water availability. Among biotic factors are density-dependent processes, as intraespecific and interespecific competition, herbivory, pathogens, phenology and seed dispersion. Investigation of tree spatial patterns, patterns in size classes, and dominant species patterns can show evidences about the structure of plant communities. Description of trees spatial pattern was made using the most appropriate statistical tools for mapped data. Ripley’s K Function has as its main attributes the power to detect the spatial patterns in different distance scales simultaneously, and to investigate spatial independence among groups of trees. Observed patterns were compared to Complete Spatial Randomness model, in univariate function, and to Complete Spatial Independence model, in bivariate function. Different forests, typical from Southeastern Brazil, were compared in this study: Forest Savanna (Cerrad˜ao), Dense Rain Forest, Seasonal Semideciduous Forest and Restinga. This mastership thesis is part of Project "Diversity, dynamics and conservation in forests in the State of São Paulo: 40 ha of permanent plots", from FAPESP Biota Program. In this project, one permanent plot of 10.24 ha was located in each forest stand, and all its trees with circunference at breast height equals 15 cm or higher were measured, mapped and identified. The results obtained in this study shows the aggregated pattern as the most common pattern in tropical forests. The trees spatial pattern in Cerradão and Restinga were very similar, aggregation was observed in the same distance scales. For the Dense Rain Forest, the spatial pattern was significant for all the distance scales. In Semidecidous Forest, a tendency towards randomness was observed, but a significant aggregation appeared for short distances. The spatial analysis for size classes showed that the newer classes have aggregated patterns, while the following classes have random ones. The dominant species spatial patterns were close to the general patterns of its community. As expected, dominant species play important rules in characterizing the horizontal pattern of their forests. Common species between different forests showed small differences in its spatial pattern, indicating the importance of its autoecology and the intrinsic ecological processes of each community.