North American Tree Rings, Climatic Extremes, and Social Disasters - Dendroclimatology - page 313

Fig. 10.11 This tree-ring reconstruction of the Palmer Hydrological Drought Index for the
Tidewater region of Virginia and North Carolina extends from AD 1200 to 1985 and illustrates
record drought during the initial English attempts to colonize America (Stahle et al. 1998 ) . The
Lost Colony of Roanoke Island disappeared during the most extreme reconstructed drought in 800
years (1587-1589), and the first successful settlement at Jamestown suffered prolonged drought
from 1606 to 1612. Thousands of settlers died during the first two decades of English colonization,
and the percent mortality was correlated with growing season moisture conditions (June PHDI,
inset left )
brackish water/freshwater front. The location of this salinity gradient in the James
River is sensitive to precipitation and streamflow (Prugh et al. 1992 ) . In dry years,
brackish water extends well upstream from Jamestown, and we know from firsthand
accounts that the settlers suffered poor water quality and ill health during these dry
years (Stahle et al. 1998 ) . The Jamestown colony ultimately survived the drought
and suffering during the first two decades of settlement to become the first success-
ful English settlement in America. The drought sensitivity of the colony appears
to have been lessened by increased support from England, expanded agricultural
production, an improved water supply, and the development of the tobacco trade.
The drought of the 1560s in the Carolinas and Virginia was part of a severe, long-
lasting drought that impacted much of the North American continent during the
sixteenth century. This multidecadal sixteenth-century megadrought was focused
over Mexico and the Southwest and persisted with little relief in some areas for
nearly 30 years (Fig. 10.12 ) . The drought appears to have developed over the far
West in the 1540s, moved into the Great Plains during the 1550s, was most intense
over Mexico and the eastern United States in the 1560s, expanded into the south-
western United States during the 1570s, and culminated in the 1580s over the Rocky