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Tree rings tell us much more than just a tree’s age. They also provide clues that help us understand how our environment has changed in the past, and provide insights into how key processes in atmosphere, biosphere and geological systems operate over long timescales.
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GEOG5839CHRONOLOGY
INTRODUCTION TO
DENDRO
2012 Mar-May temperature anomaly!h"p://www.giss.nasa.gov/
QUESTIONIs it unusual for the world to be this warm?
Low reservoir
Source: Glen MacDonald
QUESTIONIs there enough water in the Colorado River
to satisfy the expected need?
QUESTIONWhen were these dwellings constructed
(and abandoned)and why?
QUESTIONHow does weather and climate affect the risk and severity of forest fires?
Source: U.S. Coast Guard, Lt. Brendan Evans
QUESTIONHow often do natural hazards like floods occur,
and what factors make them more or less likely?
Three li"le words achingly familiar on the Western farmer's tongue, rule life in the dust bowl of the continent – if it rains.“ ”
Associated PressApril 15, 1935
There is nothing magical about the last one hundred years.“ ”
Dr. Balaji Rajagopalan University of Colorado
CLIMATE HISTORY OF NORTH AMERICA
THOUSANDS OFYEARS AGO
0
MODERNOBSERVATIONS
LAST GLACIALMAXIMUM
20 16 48
YoungerDryas
Demise of LaurentideIce Sheet
Final Drainageof Lake Agassiz
12
Tree at Chancellorsville
Source: Andy Frasse!o
Tree-ring display at elementary school
Source: Tom Swetnam
MUCH MORETHAN JUST
COUNTING TREE RINGS.
DENDROCHRONOLOGY IS
A. E. Douglass University of Arizona
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.”“
Source: Baillie (1982)
Source: Lane Johnson
Source: Lane Johnson
27
St.. George and Nielsen, The Holocene, 2003
Giant sequoia 3,266 years
Source: Julie Jordan Sco!
Source: Tom Harlan
Intermountain bristlecone pine 4,844 years
Source: Ralph Sievert
The Seward Oak 330 years?
Source: Danny Margoles
Eastern white cedar (in Minnesota) 560 years
Tree-ring analysis is one of the most powerful tools available for the study of environmental change and the identification of fundamental relationships between tree growth and climate.
“ ”Ed Cook and Neil Pederson
Lamont-Doherty Earth Observatory
I N T R O D U C T I O N T O D E N D R O C H R O N O L O G Y
GEOG5839MAJOR TOPICS
The science of dendrochronology uses information encoded into the annual growth rings of trees to address issues related to climate change, hazards, ecology and natural history.
September 6
What are tree rings?
Source: Paul Schulte
September 18
How does weather a#ect tree growth?
h!p://esp.cr.usgs.gov/data/atlas/li!le/
September 20
The principle of cross-dating
The Longest Tree-Ring Record In The Americas.
8,500 Years
October 23
The history of dendrochronology
October 18
Sampling strategies
October 16
Dendroarcheology
Source: Whitney Crawford
November 6
Dendroecology
Source: Erica Bigio
November 8
Dendrogeomorphology
GEOG5839LABORATORY ACTIVITIES
Source: Fritz Schweingruber
Exercise
Tree anatomy
Exercise(s)
Cross-dating
Exercise
Signal processing
GEOG5839ABOUT ME
GEOG5839COURSE STRUCTURE
In-class discussion
Project and final report
Laboratory exercises
Final exercise
25%
5%
40%
30%
GEOG3839NEXT CLASS
Source: Fri!s Schweingruber
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