Tree Rings and Drought
     Past drought on the Canadian Prairies


                       S co tt St. Ge orge
           ...
Prairie tree-ring network, ca. 1996
3
Fort Dufferin, Manitoba
4,000 year-old
river logs




         6
Prairie tree-ring network


                  Northern Saskatchewan




Eastern Rockies
                                  ...
4
Characteristics of
 Prairie tree rings
The tree-ring record of summer
drought in the Canadian Prairies
Scott St. George
David Meko                         Greg P...
Tree age
Bristlecone pine
  4,844 years
     Source: OLDLIST




                  Photo: Tom Harlan
Eastern white cedar
    1,653 years
      Source: OLDLIST

                        Photo: Peter Kelly
Eastern white pine
    290 years
     Source: M. Girardin
Bur oak
279 years
Limber pine
 846 years
  Source: G. Pederson




         Photo: Greg Pederson
Richard I of England   16
Photo: julie & fanu
Length of regional records
      S. Alberta                                   480


N. Saskatchewan          169


    S. ...
Seasonality
“
The trees composing the
forest rejoice and lament with
its successes and failures and
carry year by year something
of it...
Dominant seasonal signals
        90
                                          82
        80
        70
        60
       ...
21
22
Medicine Hat, Alberta




Source: Environment Canada, Adjusted Historical Canadian Climate Data, 1895 – 2006
24
Effectiveness
Dendrohydrology
works best where it’s

         dry       ...
and not so well
where it’s
     wet
Ringwidth as a proxy for
‘Lethbridge’ PDSI
Ringwidth as a proxy for
‘Dryden’ PDSI
Uncertainty
755 m3/s

847 m3/s

809 m3/s

770 m3/s

823 m3/s

787 m3/s

901 m3/s
     3
“Trees are not thermometers
       or raingauges.”
     Keith Briffa and colleagues
Quantitative drought estimates
Quantitative drought estimates
Can we
             Absolutely!
do better?
Photo: Emma Watson
Photo: New York Times




    38
Focus on long-term drought
                     100%       60%             43%
Explained variance




                    ...
Courtesy Keith Lombardo




Measure other stuff
Wood chemistry    Wood density
Stable isotopes   Wood anatomy
Prairie tree rings
          & drought

                41
Photo: Monceau




web.mac.com/scottstgeorge
Tree rings and drought on the Canadian Prairies
Tree rings and drought on the Canadian Prairies
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Tree rings and drought on the Canadian Prairies

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I've been asked to give a presentation at a workshop to be held in Alberta in March. The workshop will revolve mainly around the use of tree rings and other natural 'proxy' records to water issues in the Canadian Prairie provinces.

I'll be presenting material drawn from the last chapter of my doctoral dissertation, and will talk about the strengths and limitations of tree-ring records as indicators of past drought. The audience will include between 50 and 100 water managers from the region, and for many of them, the workshop will be their first exposure to tree rings and other forms of paleoclimatology. I think it will be in their best interest (and mine) that the scientific presentations focus more on big-picture ideas and less on technical details and methodology.

With an eye towards getting my point across more effectively, I've worked up a set of slides in the 'Presentation Zen' style. I've included more photos than I have in previous presentations, and have also tried to swap out complex journal-style diagrams and replace them with simpler graphics.

I'm excited (and a little nervous) to see how the presentation is received - I imagine its style will be quite different from the other talks in the workshop. I've posted the slides at Slideshare.net, and would appreciate any comments or suggestions - the workshop is not for another six weeks, so I have plenty of time left to tweak or change my plans.

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  • Congratulations great work !!! .. Thanks for sharing ! …Environmental, save the planet, conserve and protect nature, awareness globally,,are a few goals of 'GREAT CAUSE and JUST CAUSES' Group. (au sens large du terme) Very nice... Great work ! !Thanks for sharing,. Best regards . Bernard (France)
    Do not hesitate to reference your slideshows on the group ''GREAT CAUSES and JUST CAUSES '. Thank
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  • Thanks for sharing these lovely photos of trees that have been here long before us. I love looking at trees. Look up and you can see their branches lacing the sky. Lovely sight.
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Tree rings and drought on the Canadian Prairies

  1. Tree Rings and Drought Past drought on the Canadian Prairies S co tt St. Ge orge Geological Survey of Canada
  2. Prairie tree-ring network, ca. 1996
  3. 3
  4. Fort Dufferin, Manitoba
  5. 4,000 year-old river logs 6
  6. Prairie tree-ring network Northern Saskatchewan Eastern Rockies Northwestern Ontario Southern Manitoba
  7. 4 Characteristics of Prairie tree rings
  8. The tree-ring record of summer drought in the Canadian Prairies Scott St. George David Meko Greg Pederson Martin-Phillippe Girardin David Sauchyn Glen MacDonald Jacques Tardif Erik Nielsen Emma Watson Submitted to the Journal of Climate, January 2008
  9. Tree age
  10. Bristlecone pine 4,844 years Source: OLDLIST Photo: Tom Harlan
  11. Eastern white cedar 1,653 years Source: OLDLIST Photo: Peter Kelly
  12. Eastern white pine 290 years Source: M. Girardin
  13. Bur oak 279 years
  14. Limber pine 846 years Source: G. Pederson Photo: Greg Pederson
  15. Richard I of England 16 Photo: julie & fanu
  16. Length of regional records S. Alberta 480 N. Saskatchewan 169 S. Manitoba 485 NW Ontario 225 0 125 250 375 500 Years
  17. Seasonality
  18. “ The trees composing the forest rejoice and lament with its successes and failures and carry year by year something of its story in their annual rings. ”Douglass A.E.
  19. Dominant seasonal signals 90 82 80 70 60 50 Sites 40 30 24 20 10 7 3 0 20 Autumn Winter Spring Summer Autumn
  20. 21
  21. 22
  22. Medicine Hat, Alberta Source: Environment Canada, Adjusted Historical Canadian Climate Data, 1895 – 2006
  23. 24
  24. Effectiveness
  25. Dendrohydrology works best where it’s dry ...
  26. and not so well where it’s wet
  27. Ringwidth as a proxy for ‘Lethbridge’ PDSI
  28. Ringwidth as a proxy for ‘Dryden’ PDSI
  29. Uncertainty
  30. 755 m3/s 847 m3/s 809 m3/s 770 m3/s 823 m3/s 787 m3/s 901 m3/s 3
  31. “Trees are not thermometers or raingauges.” Keith Briffa and colleagues
  32. Quantitative drought estimates
  33. Quantitative drought estimates
  34. Can we Absolutely! do better?
  35. Photo: Emma Watson
  36. Photo: New York Times 38
  37. Focus on long-term drought 100% 60% 43% Explained variance 75% 50% 57% 40% 25% 0% Single Year 5-Year Average
  38. Courtesy Keith Lombardo Measure other stuff Wood chemistry Wood density Stable isotopes Wood anatomy
  39. Prairie tree rings & drought 41
  40. Photo: Monceau web.mac.com/scottstgeorge
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