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The annual growth rings from trees provide us with an incredibly powerful and adaptable tool to study Earth’s history. The rings tell us much more than just the age of tree. 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.This course will teach students the fundamental principles of dendrochronology through a combination of formal lectures, class discussion and laboratory exercises. Students will work in the University of Minnesota’s Center for Dendrochronology, where they will learn how to collect, prepare and date tree-ring specimens. By the end of the course, they will be able to explain both the key concepts underlying dendrochronology and discuss how evidence from tree rings is used to address contemporary issues in natural history, resource management and Earth Systems Science.
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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
2010 Dec-Nov temperature anomaly h"p://www.giss.nasa.gov/
NASA global temperature record h"p://www.giss.nasa.gov/
QUESTIONIs it unusual for the world to be this warm?
Water transfers in the American southwest
Courtesy Glen MacDonald
Low reservoir
Photograph: Glen MacDonald
QUESTIONIs there enough water in the Colorado River
to satisfy the expected need?
Photograph: watsonsinelgin
Photograph: Howard Arno!
QUESTIONWhen were these dwellings
constructed (and abandoned)and why?
Photograph: Tom Swetnam
Photograph: WhineAndDine
QUESTIONHow does weather and climate affect the
risk and severity of forest fires?
Photograph: Greg Brooks
Red RiverManitoba
AP Photo/U.S. Coast Guard, Lt. Brendan Evans
QUESTIONHow often does the Red River
produce extreme floods?
Tree at Chancellorsville
Photograph: Andy Frasse!o
Tree-ring display at elementary school
Photograph: Tom Swetnam
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.”
“
Same environmental conditions
Similar growth pa"erns
25
1900 1910 1920 1930
Two Douglas-fir cores from Eldorado Canyon, CO
Graphic: Jeff Lukas, INSTAAR
THE PRINCIPLE OF CROSS-DATING
Photo: Howard ArnottFrost damage Photograph: Howard Arno!
Fire scars
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.
Photo: Chris MullinsGiant sequoia 3,266 years Photograph: Chris Mullins
Bristlecone pine 4,844 years Photograph: Tom Harlan
White pine 1714
Photo: Kurt Kipfmueller
Photo: Danny Margoles
White cedar 1452
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
Fundamentals Tree-ring anatomy Photograph: Kevin Anchukaitis
Fundamentals Weather, climate and tree growth Photograph: dr_tim_1956
Fundamentals History of dendrochronology
Fundamentals Statistical tools for tree-ring analysis
Applications Drought risks Photograph: Library of Congress
Applications Fire ecology Photograph: Don Falk
Applications Natural hazards and landscape processes Photograph: Erica Bigio
Applications Forest ecology Photograph: Whitney Crawford
43Applications Maritime archeology
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
Who am I?
Tree-ring display at elementary school
Photograph: Tom Swetnam
Photograph: Dave Sauchyn
Photo: Calvin Ferris Kurt Kipfmueller University of Minnesota
umndendro.umn.edu
GEOG3839 Nuts and boltsGEOG5839
Links to course syllabus, scheduleat h!p://umn.edu/~stgeorge under ‘Teaching’
GEOG3839
Mid-term
Exercises (4)
Final exam
30%
40%
30% GEOG5839
Mid-term
Exercises (4)
Project
20%
40%
40%
G R A D I N G W E I G H T S
Trees are among the oldest living things on our planet. Many trees can live for several centuries and a few exceptional specimens have survived for more than 5,000 years. In part because of their great age, the annual growth rings from trees provide us with an incredibly powerful and adaptable tool to study Earth’s history. The 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.
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. Because tree vitality is strongly influenced by local environmental conditions, major events such as a change in climate, insect a!ack or severe flood o"en create a distinct ‘fingerprint’ in the tree’s rings. By studying these signatures in the rings, we can develop an annual record of past environmental events extending back several centuries or millennia.
Links to course syllabus, scheduleat h!p://umn.edu/~stgeorge under ‘Teaching’
Readings!Smith and Lewis (2006), Dendrochronology
What can you expect to learn?
DENDROCHRONOLOGY is much more than just counting tree rings
