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 and nearly 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.co m/cgi- bin/documentv1?DBLIST =cd01&DOCNUM=5592 8&TERMV=253:4:333:5: 21004:4:36400:4 http://libpub.dispatch.co m/cgi- bin/documentv1?DBLIST =cd01&DOCNUM=5592 8&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.ht m http://www.ltrr.arizona.edu/skeletonplot/plotting.ht m Step 2: Cross-dating  Match pattern with a master chronology  http://www.ltrr.arizona.edu/skeletonplot/patternmat ching.htm http://www.ltrr.arizona.edu/skeletonplot/patternmat ching.htm