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Tree ring age dating

Modern dendrochronologists seldom cut down a tree to analyze its rings.

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For example, archaeologists use tree rings to date timber from log cabins and Native American pueblos by matching the rings from the cut timbers of homes to rings in very old trees nearby.Through the study of annual growth rings of these trees, a fairly precise method of absolute dating has been obtained.So far, this amazing record from the Bristlecone pines only applies to the southwestern portion of the United States and has become useful also to the field of archaeology where ancient roof beams have been more accurately dated using the tree-ring growth records.Activity Answers The answers to some of the questions will depend upon the class, for example, when the students were born.In looking at the climate record as revealed in the tree rings, notice that there is a significant period of poor growing conditions in each of the four decades covered by the tree samples.Computers are used to detect possible patterns and cycles from these sources.

In dendrochronology, large databases allow scientists to compare the ring records of many trees, construct maps of former regional climates, and reveal when, where, and how quickly the climates changed.

If the rings are a consistent width throughout the tree, the climate was the same year after year.

By counting the rings of a tree, we can pretty accurately determine the age and health of the tree and the growing season of each year.

Modified with permission from Global Change: Time and Cycles, Department of the Interior, U. Students will be able to recognize the direct impact of climate on annual tree growth patterns.

In this activity, students will use pre-marked paper strips to simulate tree-ring core samples to help them understand that data for past climate changes can be gathered from sources beyond long-term weather observations.

Background Trees contain some of nature's most accurate evidence of the past.