This document discusses dendrogeomorphology, which is the study of geological evidence contained within tree rings. It provides three examples of studies using dendrogeomorphology to reconstruct past natural hazards: 1) A 1997 Nature study used tree rings to show that an earthquake and tsunami damaged the Cascadia subduction zone along the west coast of North America between 1700-1720. 2) Tree rings were able to converge on the year 1700 to show that earthquake hazards could affect Canada and the northwest U.S. 3) Dendrogeomorphic studies of trees in hazardous locations tend to be short because trees do not live long in such areas.

1. November 8
Dendrogeomorphology
Source: Erica Bigio

2. HOW STABLE
IS THIS
MOUNTAIN SLOPE?
Source: slgwv

3. HOW OFTEN
DOES THIS
RIVER FLOOD?
Source: Nic McPhee

4. HOW FAST
CAN THIS
GLACIER MOVE?
Source: Bob Sanford

5. Source: Julian Lozos
Sudden change in ring-width and color a er the 1812 New Madrid earthquake.

6. “ A visual inspection of the increment rings will in no case
allow determination of the process that was causing
the disturbance.
”
Markus Stoffel and Michelle Bollschweiler
Natural Hazards and Earth System Sciences, 2008

7. “ Geomorphology ma ers!
Markus Stoffel and Michelle Bollschweiler
Natural Hazards and Earth System Sciences, 2008
”

8. PROCESS • EVENT • RESPONSE

9. PROCESS • EVENT • RESPONSE
debris flows A specific
Wounded tree
(in general) debris flow
(scars)
event

10. MASS MOVEMENTS
GLACIERS
DEPOSITION

11. MASS MOVEMENTS

12. Source: Munir Squires
Earthflows are downslope, viscous flows of saturated, fine-grained materials.

13. Source: darkensiva
A debris flow is a fast moving, liquefied landslide of unconsolidated, saturated debris.

14. Source: Washington State Department of Transportation
A rockfall is the downward motion of a rock involving free falling, bouncing, rolling, and sliding.

15. How do mass movements
affect the growth of trees
or the demography of forests?

18. Source: Erica Bigio

19. Source: Stoffel and Bollschweiler, 2008

20. How can you distinguish the scars caused by mass movements
from those caused by wildfire?

21. IMPACT FIRE

22. “ Geomorphology ma ers!
Markus Stoffel and Michelle Bollschweiler
Natural Hazards and Earth System Sciences, 2008
”

23. Source: Brian Luckman

24. Source: Brian Luckman

25. Abrasion or impact scars
are NOT
the sole source of geomorphic evidence.

26. Source: Brian Luckman

27. Source: snebtor

28. “ Partial uprooting can cause smaller trees to form
vertical sprouts along their main stem, with the
age of the sprout indicating the date of the flood
”
that caused the change in growth habit.
Sco St. George
Tree Rings and Natural Hazards, 2010

29. Source: Erica Bigio

30. Compression wood
• forms in conifers
• formed on lower side of
tree
• wider rings
• more latewood
• denser and more bri le
• tracheids are heavily
lignified

31. Tension wood
• occurs in hardwoods
• formed on the upper
side of the lean
• fewer (and smaller)
vessels
• increased production of
thick-walled fibers
• reduced amount of
lignification

32. Pinyon Demography at Sevilleta LTER, Central New Mexico
Source: Betancourt et al. (2004)

33. Age of trees growing on rockfall slope Stoffel, Schneuwly and Bollschweiler 2010

34. Reconstructed rockfall frequency near Valais, Switzerland Schneuwly 2010

35. Glacial advances and retreats

41. Source: Dan Smith
Sheared stumps killed by advance of the Saskatchewan Glacier circa 2800 yr BP

42. GLACIAL
FOREFIELD

43. Photograph: Brian Luckman

44. The ecesis interval is the amount of time between
an initial disturbance and the successful establishment
of the first trees.

45. Conifers on forefields ‘ecize’ in ca. 5 to 60 years.
(McCarthy and Luckman, 1993)
Source: Brian Luckman

46. Source: avern

47. Source: Luckman, Geomorphology, 2000

48. Burial and erosional processes

49. Jasper Lake Alberta, Canada

50. “ Dust accumulations measured at Jasper Lake, a
seasonally-filled reach of the glacially- fed Athabasca
River in the Canadian Rocky Mountains, are some of
”
the highest contemporary rates recorded to date.
Chris Hugenholtz and Steve Wolfe
Geomorphology, 2010

52. Modern surface
Germination surface

53. “Adventitious” roots

54. Adventitious roots

55. Source: Erica Bigio

56. November 8
Dendrogeomorphology
Source: Erica Bigio

57. 1964 Alaskan earthquake

59. “ Geological evidence shows that an earthquake
a ended by a tsunami, or a series of such earthquakes,
ruptured at least 900 km of the Cascadia subduction
”
zone along the west coast of North America between
the years 1700 and 1720.
David Yamaguchi et al.
Nature, 1997

60. Source: Teachers on the Leading Edge

61. Source: Teachers on the Leading Edge

62. Source: Teachers on the Leading Edge

64. “ By converging on January 1700, the dates mean that
Canada and the northwestern United States are
plausibly subject to earthquakes of magnitude 9.
”
David Yamaguchi et al.
Nature, 1997

65. “ The reason that most [dendrogeomorphic] studies tend to be
relatively short is because the life expectancy of trees
growing in [dangerous locations] is comparatively brief.
”
Sco St. George
Tree Rings and Natural Hazards, 2010

66. “ Geomorphology ma ers!
Markus Stoffel and Michelle Bollschweiler
Natural Hazards and Earth System Sciences, 2008
”

67. GEOG8280
XT C L AS S
NE
h p://www.cru.uea.ac.uk/cru/people/briffa/temmaps/