Great Moments in Dendrochronology

1. Great MomentsinDendrochronology Paul Sheppard

2. Forestry Major Humboldt State University, California

3. Forestry Major • Tree identification • Forest ecology/biogeography • Silviculture • Production • Dendrochronology

4. Dendrochronology = tree-ring science

5. UA Tree Rings

6. Dating Climate Fire Geology Water Chemistry

7. Eternal question • Why do you do what you do?

9. Eternal question • Why do you do what you do? • Eternal answer • Put modern times in context of deep past • Eternal come back • Yea, yea, but give examples! • Great Moments in Dendro

10. Bridging the Gap

14. AndrewEllicottDouglass

15. 2014 1050

17. The Gap

18. Show Low • Buried log

21. Universal Accolades • “most valuable contribution ever made to American archaeology” • “most important thing ... thus far in American prehistory” • “your contribution … is singularly outstanding” • “tree-ring approach has been the single greatest contribution ever made to American archaeology”

22. Bridging the Gap • Interesting, hard problem • Huge data set • Thousands living trees, Sky Islands • Hundreds beams, dead trees • Took 20+ years of work • Multidisciplinary • Dendro, archaeo, geogr • First great moment

23. Radiocarbon Date Check

24. 14N 14C into plants, animals they die half-life =5730 yrs 14N

25. Obvious Experiment • Try C14 dating of wood already dated by dendrochronology • Should result in a 1:1 line in a scatter plot • If not … ?

26. Irish oak: 9,000 years • US bristlecone pine: 8,700 years • German oak-pine: 12,500 years

27. C14 vs dendro of wood 800 years!!! 6000 BC AD 2000

30. Electromagnetic strength

31. Radiocarbon Date Check • Interesting, hard problem • Huge data set • Hundreds of trees, living dead • Took tens of years of work • Multidisciplinary • Dendro, phys, chem, astro • Spectacular moment!

33. Colorado River

34. Colorado River Compact, 1922 • 4th from left?

35. Colorado River Compact • WY, CO, UT, NM – Upper Basin • AZ, NV, CA – Lower Basin • 7.5 maf for each basin per year • Extra 1 maf for Lower Basin (CA) • Total: 16 maf every year

36. Colorado River Watershed • Abundant, long-lived trees, Sky Islands • Statistical relationship ring width and gauge record  river flow

37. Reality Check • Past 450 years: • Average: 13.5 maf • Range: 4.4 – 22 maf • 1922 was high!

38. Updated recently • 15 maf • 1920s still high • 1100s?

39. Testimony to State Govt.(March 3, 2003, AZDS,Drought in West may last decades) • Expert: The current drought in Arizona could conceivably last for 20-30 years. • Agency official: “We hope all this stuff about the ocean [and our rainfall] turns out to be wrong.”

41. Colorado River • Interesting, hard problem • Huge data set • Thousands of living trees • Took tens of years of work • Multidisciplinary • Dendro, hydro, geogr, stats • Compelling great moment

42. Other Great Moments • Forest fire history • Profound ecological change, Sky Islands • Drought atlases • North America, Asia, Europe • Dating, discovering past earthquakes • San Andreas fault • Dating past volcanic eruptions • Sunset Crater, Arizona

43. Potential GM: Global Warming

44. Global Warming? • Instrumental record shows warming • Ocean or land • Now: warmest years are 1.8 °F above coolest years • Is this unusual in the long term?

45. Paleo Temperature • Worldwide temperature reconstruction • Tree rings, ice,pollen, corals

46. Paleo Temperature • Last 1300 years: Current warming is unusual

48. Potential GM: Global Warming • Interesting, hard problem • Huge data set • Thousands of trees, living & dead • Ice, pollen, corals, sediments • Weather data worldwide • So far: decades of work • Multidisciplinary • Dendro, ocean, neo-paleoclime, policy • Tree rings on global warming: Great?

50. Questions, comments?