Presentation on theme: "Intro to Tree-Ring Dating Jan 12, 2009. Crossdating."— Presentation transcript:
Intro to Tree-Ring Dating Jan 12, 2009
Crossdating is the procedure of matching and synchronizing ring-width patterns among trees that have grown in nearby areas, allowing the identification of the exact year in which the ring was formed. Dated and measured rings from a number of trees in a region are combined to form a tree- ring chronology.
Crossdating A tree-ring chronology must have at least 50 trees or wood samples from the same genus. This will decrease the influence of noise. The chronology can be used as a tool for dating events that caused tree death or a marked change in the appearance of a ring or set of rings.
Anomalies in Ring Growth Missing ring – a ring that is entirely absent from a tree Locally absent ring – a ring that is not present throughout the entire circumference of the tree
False ring – when it appears that more than one ring has been created in 1 growing season Anomalies in Ring Growth
Skeleton Plots Skeleton plot is a graphical representation of ring width patterns, used in crossdating. du/skeletonplot/Skeleto nPlot19.htm