To provide access without cookies would require the site to create a new session for every page you visit, which slows the system down to an unacceptable level.
Tree-ring series can be classified as either complacent (uniform ring widths where moisture and heat are sufficient throughout the growing season) or sensitive (pronounced year to year variation in ring width, where conditions are frequently near the limits of the trees tolerance, e.g. The search for proxy climatic data was the original application of tree rings. In 1901, he noticed ring-width variations on a cut log and reasoned that these were controlled by the tree's environment (Fritts, 1976).
Douglass (1920) illustrated the relationship between climate and ring width by plotting both against time, and introduced the technique of cross dating by correlating ring-width signatures (sequences of wide and narrow rings) among trees distributed over large areas.
Wolffia using a increment borer to age-date an old sierra juniper (Juniperus occidentalis var.
Dendrochronology, the study of the annual growth in trees, is the only method of paleoenvironmental research that produces proxy data of consistently annual resolution. Initially the cells are thin walled to conduct the abundant spring soil moisture.
Close-up view of the increment borer, showing the slender wood core that is extracted from the trunk.
The core is sanded and treated with a wood oil to make the rings more distinct.
For pine (O time series were more strongly correlated than ring-width series.
In some instances within-tree, ring-width series (multiple cores from each tree) were not significantly correlated, again indicating that using ring-width data for cross-dating redwood can be problematic.