October 25

The history of dendrochronology

RINGS IN THE BRANCHES OF SAWED TREES SHOW

THE NUMBER OF YEARS AND, ACCORDING TO THEIR

THICKNESS, THE YEARS WHICH WERE

MORE OR LESS

DRY.

“ ”

Leonardo da Vinci

Photograph: Anshul Nigham

... and if one forces a stone or similar object into a tree, it becomes hidden, since the new growth surrounds it, as was the case with the wild olive treewhich stood in the market place at Megara.

“ ”Theophrastus (371 - 287 BC)

Henri-Louis Duhamel du Monceau1700 - 1782

Georges-Louis Leclerc, Comte de Bu!on1707 - 1788

Photograph: Fri!s Schweingruber

Frost ring Pinus sibirica

1737➟1708

Alexander Twining1801 - 1884

“...every tree told the same story.”

Tucson, AZ

ANDREW ELLICOTTDOUGLASS

Flagsta!, AZ

Andrew Douglass (right) Flagsta! 1898

Source: Sam Wise

Lowell Observatory Flagsta! Arizona

Source: Schiaparelli (1888)

Tucson, AZ

Photograph: Howard Arno!

Photograph: Christine and John Fournier

We do not know how old these ruins are, but I should be glad to have an opinion from you as to whether it might be possible to connect up with your modern and dated trees specimens [with wood specimens] from these [prehistoric] ruins by correlating the curves of growth…

“ ”Clark Wissler to A.E. Douglass

1909

Aztec Ruin

Publo Bonita

Source: Sco" Catron

Aztec Ruin National Monument New Mexico

Source: Chris M

Pueblo Bonito New Mexico

Pueblo Bonito New Mexico (before it was excavated)

Source: Stones 55

Wupatki New Mexico

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Living-tree chronology

‘Floating’ chronology

National Geographic ‘Beam Expeditions’ 1923 and 1929

Show Low, AZ

$5for

100 rings

$65for

100 rings2011 dollars

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120011001000900800700

Living-tree chronology

‘Floating’ chronology

HH-3913801237

For the three of us, the experience was unforge"able. To be present at the instance of the celebrated breakthrough in science that set the chronological house in order for the Southwestern United States was reward enough. But beyond that, was the privilege to work for a time at the side of Douglass, the scholar, the astronomer turned archaeologist.

“ ”Emil Haury

1962

Tree-ring display at elementary school

Photograph: Tom Swetnam

GEOG8280NEXT CLASS