Dendrochronology cross dating
However, prior to any proxy-based climate or environmental reconstruction, a calibration between the proxy archive and an instrumental series is required.
Dendrochronology techniques were applied to the marine bivalve to demonstrate the benefits of visual crossdating and replication of growth series (growth within one shell and between multiple shells in the same population).
Example: analyzing changes in tree growth patterns via tree rings to date a series of landslide events.
The science that uses tree rings to date and study past and present changes in glaciers.
First, the strength of a common growth signal (how synchronous growth is at the population level) must be determined at each site.
Then, ecologically relevant comparisons with environmental can be investigated.
Example: dating the tree rings of a beam from a ruin in the American Southwest to determine when it was built.
Even in relatively straightforward cases, all methods employed are sometimes found to produce spurious dates or to fail to identify a known correct match.
Since cross-dating depends on matching the high-frequency elements of a sample against a master chronology, various methods are explored for removing the low-frequency variance in ring-width series before they are compared.
The results show that a range of such “pre-whitening” methods can usefully be employed, and no single method is universally superior.
Example: analyzing ring widths of trees to determine how much rainfall fell per year long before weather records were kept.
The science that uses tree rings to study factors that affect the earth's ecosystems.