We DO NOT give "possible" dates or dates with a plus or minus factor!
While crossdating is the central principle in dendrochronology, cognitive classification is the central concept of (successful) crossdating. Tree-ring scientists rely heavily on visual inspection and microscopic examination of wood specimens so that we can ensure that we have assigned the correct calendar (or relative) year to the tree ring.
Example: dating the fire scars left in tree rings to determine how often fires occurred in the past.
The science that uses tree rings to date and study the past dynamics of insect populations.
Example: analyzing the effects of air pollution on tree growth by studying changes in ring widths over time.
This is because, as a scientific discipline evolves, so too must the principles to which it adheres. I kept adding new principles while simultaneously revising or even deleting long familiar principles.Example: dating the tree rings of a beam from a ruin in the American Southwest to determine when it was built.The science that uses tree rings to study present climate and reconstruct past climate.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.Example: dating when trees were inundated by water to determine the sequence of lake level changes over time.The science that uses tree rings to date and study past and present changes in wildfires.In fact, the introduction of "divergence" into the dendro-lexicon in the late 1990s epitomized the changing response of trees to climate over time, first scrutinized in detail in the mid-1980s. Perhaps it actually "Paradoxically, in suggesting that this term now be dropped from use, we pay a most fitting tribute to its vital role in the history of geology." -- Stephen Jay Gould, 1965, "Is uniformitarianism necessary"?This principle states that matching patterns in ring widths or other ring characteristics (such as ring density patterns) among several tree-ring series allows the identification of the exact calendar (or relative) year in which each tree ring was formed.Over the past three years, I have been working on revising these principles and I've presented numerous talks across the U. Eventually, I settled on the principles below as being representative of those to which we actually should adhere and have been adhering.I've sought input from individuals on these revisions and to all of them I'm especially grateful. One glaring change is that you will no longer notice the inclusion of the Principle of Uniformitarianism (or Uniformity).