Dendrochronology
Dendron = tree; chronos = time
 Annual rings and the environment
 Applications
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Fire history
Historical droughts
History of Stradivari string instruments
A few photographs are the courtesy of Henri Grissino’s Web Page.
http://web.utk.edu/~grissino/
Dendrochronology
Dendron = tree; chronos = time
the science that assigns dates to tree rings in order to
answer questions in variety of natural studies
Potential Uses:
Archaeology
Climatology
Hydrology
Pyrochonology
Volcanology
Tree Rings Provide Information on Past
Precipitation and Temperature
 Density--brightness or
darkness of the ring is
associated with mean
temperature of that
year
 Dark rings = more
lignin and secondary
cell wall which forms
in warm weather
Tree Rings Provide Information on Past
Precipitation and Temperature
 Ring Width is determined by
precipitation during growing
season
 Ring Density is associated
with temperature of growing
season
In moist uniform climates,
variation in annual ring width
is diminished.
Rings are uniform in this
environment.
87 year old ADK Hemlock
Giant Redwoods Provide
Information on Fire History
 Redwoods occupy fire prone regions
 Thick redwood bark protects tree
from low intensity fires
 Fire scars on trees leave a unique
pattern in tree rings
Giant Redwoods Provide
Information on Fire History
 Vascular cambium
regenerates near the wound
 Eventually tree grows new
tissue over the wound
Giant Redwoods Provide
Information on Fire History
 Fire scars can be aged
by counting tree rings
 Determine frequency
of past fires and the
intensity of fires
Giant Redwoods Provide
Information on Fire History
 Tree rings following fires are
often wider than prior to the fire
 Fires were more frequent in past
and burned at a low intensity
Judgment Day in New England
May 19, 1780
 New England’s Dark Day
 Midday meals by candlelight
 Blackness filled the air
The Lost Colony of Roanoke
& the fall of Jamestown
 English associates last visited
members of Roanoke Colony on
August 22, 1587
 Two years later all members of
Colony were gone
 Jamestown in 1607 38 of 104
colonizers died in the first year
 Jamestown-4800 of 6000
additional colonist died between
1607 and 1625
What happened to Roanoke Colony and
Jamestown?
 British suggested that colonist planned
poorly—insufficient food and clean water
 Dendrochronology (800 year record) of
Bald Cypress in SE United States—1998
 1587-1589—worst drought in 800 years
 1606-1612—worst seven year drought in
700 years
 What problems did drought cause?
Stradivari Violins & Dendrochronology
 High quality violins from
17th century (Golden Age)
 Maunder Minimum

Reduced solar activity
• Cool moist summers
• Reduced growth
• Uniform growth
 Climate and Environment
contribute to Golden Age
of String Instruments
Physisporinus vitrius
Xylaria polymorpha