North American Tree Rings, Climatic Extremes, and Social Disasters - Dendroclimatology - page 318

data from Durango, Mexico, indicate intense drought spanning the period 1453-
1455, being most intense in 1454. The 'Drought of One Rabbit' in 1454 seems to
have contributed to the Aztec superstition regarding all One Rabbit years, which
were feared for their association with famine and calamity. The available tree-ring
data fromMexico supply some substance to this superstition, indicating that drought
occurred in most of the Thirteen House years immediately prior to the One Rabbit
years of the Aztec traditional history (10 of 13 cases from AD 882 to 1558), which
would have reduced crop yields and could have contributed to hunger and hardship
during the subsequent One Rabbit years (Therrell et al. 2004 ) .
The network of 850 climate-sensitive tree-ring chronologies developed across
North America by the dendrochronological community, and used by Cook et al.
( 2004 ) to reconstruct the summer PDSI, fulfills the potential demonstrated by
Douglass ( 1929 , 1935 ) when he compiled the first master tree-ring chronology based
on living trees and archaeological timbers. The new network and the derived recon-
structions confirm the Great Drought in the late thirteenth century, which was most
intense over the Anasazi cultural area on the Colorado Plateau and persisted for
at least 21 years (Fig. 10.15 ) . However, the precise role of climate in the devel-
opment and decline of the Anasazi on the Colorado Plateau remains controversial.
Paleoenvironmental information, including tree-rings, indicates that environmen-
tal conditions of the period 950-1130 were relatively favorable (Dean 1988 , 1996 ;
Dean and Funkhouser 1995 ) . During this interval, Anasazi populations expanded to
their maximum geographical extent and achieved their greatest sociocultural com-
plexity in the regional interaction system focused on Chaco Canyon, New Mexico
Fig. 10.15
Tree-ring-reconstructed
summer PDSI is mapped
from 1276 to 1297 (see
Fig. 10.2 ) and illustrates
moderate drought or worse
for the entire 21-year episode
centered over the Anasazi
cultural area, as first
documented by A.E.
Douglass ( 1929 , 1935 ) . This
drought has been implicated
in environmental degradation
and Anasazi abandonment
across much of the Four
Corners region