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DENDROCHRONOLOGY

DENDROCHRONOLOGY. What is dendrochronology?. Dendrochronology : ology : the study of chronos : time, or more specifically events in past time dendros : using trees, or more specifically the growth rings of trees. What is dendrochronology?. Tree-rings: Each ring is a year of growth

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DENDROCHRONOLOGY

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  1. DENDROCHRONOLOGY

  2. What is dendrochronology? • Dendrochronology: • ology: the study of • chronos: time, or more specifically events in past time • dendros: using trees, or more specifically the growth rings of trees

  3. What is dendrochronology? • Tree-rings: • Each ring is a year of growth • Each year has early wood (light-colored) & late wood (dark-colored)

  4. What is dendrochronology? • How do we get wood samples? • If the tree is living, we take a core

  5. What is dendrochronology? • How do we get wood samples? • If the tree is dead, we take a cross-section of the whole tree

  6. What is dendrochronology? • The Life of a Tree • 1769 AD - The tree began from seed • 1867 - The tree was 4 inches in diameter and 26 feet tall when Alaska was purchased from the Russians. • 1917 - The tree was nearly 6 inches in diameter and 37 feet tall during WW I. • 1959 - The tree was 22 inches in diameter and 77 feet tall when Alaska became the 49th State. • 1977 - The tree was 25 inches in diameter andnearly 90 feet tall when it was felled.

  7. Why is it important? • Using tree-rings, we can learn about: • Past fires: • The white arrows indicate distinct fires of the past • Each of those fires has been dendrochronologically dated to the year it burned • This research is being done at U of A in the Tree-ring Lab

  8. Why is it important? • We can also learn about: • climatology: past droughts or cold periods • geology: past earthquakes, volcanic eruptions • anthropology: past construction, habitation, and abandonment of societies

  9. Why is it important? • We can learn about how trees respond to changes in the environment (physiology) • Chemical analysis of rings can determine rates of water loss & photosynthesis through time • By measuring width of rings, can estimate growth rates of trees through time & understand what affects tree-growth

  10. Why is it important? • Many possibilities • Such as settling the age of an historic violin • http://libpub.dispatch.com/cgi-bin/documentv1?DBLIST=cd01&DOCNUM=55928&TERMV=253:4:333:5:21004:4:36400:4

  11. How do we date tree-rings? • Do we simply count them? • No! • Trees are trickier than that, some years they don’t grow at all • This creates “missing rings” • Sometimes we just have part of a tree, not the whole tree like the violin • This is why we use pattern matching & match sections of growth with other trees

  12. How do we date tree-rings? • Step 1: Making skeleton plots • http://www.ltrr.arizona.edu/skeletonplot/plotting.htm • Step 2: Cross-dating • Match pattern with a master chronology • http://www.ltrr.arizona.edu/skeletonplot/patternmatching.htm

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