DEVELOPMENT AND CLIMATIC ANALYSIS OF A 456 YEAR TREE RING CHRONOLOGY FROM NORTHEAST OHIO, USA

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DEVELOPMENT AND CLIMATIC ANALYSIS OF A 456 YEAR
TREE RING CHRONOLOGY FROM NORTHEAST OHIO, USA
DEVELOPMENT AND CLIMATIC ANALYSIS OF A 456 YEAR
TREE-RING CHRONOLOGY FROM NORTHEAST OHIO, USA
Introduction Tree-ring series developed from
old growth oak forests in Northeast Ohio are
sensitive records of past moisture variability
and have been used, together with a larger
network of chronologies, to reconstruct drought
histories on a continental scale. Here we
describe the development and extension of
ring-width records for Northeast Ohio from living
oaks and from timbers in historical buildings.
409 series from 10 old growth remnant forests and
16 historical sites are combined into a regional
ring-width chronology that spans AD 1550-2005.
These series are positively correlated with
summer precipitation, the summer Palmer Drought
Severity Index and streamflow in the region. The
five most-narrow rings (1699, 1748, 1810, 1839
and 1895) are inferred to have been extremely dry
summers. Years 1699 and 1810 are linked to high
latitude cooling associated with large-scale,
volcanic events recognized in ice cores, but are
of uncertain origin. Living trees show a general
increase in ring-width over the last 150 years
that is poorly understood, but may be related to
the widespread forest disturbance and recovery
after settlement in the early 1800s. Development
of this record together with a more regional
analysis and mapping of extreme years and
long-period trends are ongoing. This work is
leading to new insights into understanding
drought and forest growth in the North American
Midwest.
Lehmann, Sophie1, Belding, Elyssa1, Wiles,
Gregory1, and Brush, Nigel2 (1) Department of
Geology, The College of Wooster, 1189 Beall Ave,
Wooster, OH 44691 (2) Geology, Ashland
University, 401 College Ave, Ashland, OH 44805
Figure 4 This graph represents the entire span
of the NEO chronology (1550-2005) as standardized
indices of tree ring width variability. The five
narrowest rings in the chronology are indicated
with asterisks (1895, 1839, 1748, 1699 and 1810).
1895 is a major drought year and correlates with
the second driest year in Ohio. The narrow rings
of 1699 and 1810 are concurrent with large-scale
volcanic events of unknown origin, suggesting a
link of cooling at higher latitudes in the
Northern Hemisphere (DArrigo and Jacoby, 1999)
and drought. Interestingly, similar large-scale
volcanically induced cooling and drying are not
part of the observational record. Perhaps the
years 1748 and 1838 could also be years of low
moisture not related to volcanic induced events.
Methods and Procedure An increment borer allows
us to core a 5 mm cross section from living trees
while a chainsaw is used to collect
cross-sections of timber from fallen structures
and discarded beams. In order to sample houses
and historical structures, an electric hand corer
extracts a core from a beam in an old structure
with no harm. All the cross-sections and cores
in the Northeast Ohio (NEO) Chronology were
brought back to the Wooster Tree Ring Lab where
they were sanded and analyzed under a dissecting
microscope for the ring-widths. Determining the
age of the outermost ring differs depending on
where the sample came from. The outermost ring on
cores extracted from living trees are dated to
the most recent growing season. The age of the
outermost ring on dead trees cannot be determined
until all the rings are measured, thus, the data
from such a location are formed into a floating
chronology without a calendar date. The
successive annual widths are measured to the
nearest 0.001 mm. Each location is then
crossdated (Fig. 1) against each other and the
formed master chronology to check for strong
correlation within the series.
Figure 5 The NEO ring-width series was compared
with a long monthly (1888-2003) precipitation
record from the Ohio State Agricultural and
Development Center located centrally in the study
area. A common period of 112 years was used to
correlate monthly temperature and precipitation
values for the dendroclimatic year starting in
March of the previous year through October of the
year of growth. The strongest correlations are
with June and July precipitation of the growth
year with a correlation of 0.48 (plt0.0001). A
strong negative relationship with June
temperatures is also noted and is likely due to
the high intercorrelation of temperature in June
with precipitation. Cooling in June is
associated with wetter conditions favorable for
tree growth. Comparison with mean summer PDSI
series with a common 104-year period (1900-2003)
yields a correlation of 0.43 (plt0.0001).
Figure 3 The cropped raw ring width chronology
is divided into the chronologies of living oaks
and timber from historical structures in the
area. While the series count is strong after the
early 1600s, before this time there are minimal
series and therefore earlier data must be
considered with caution. The NEO chronology is
considered a regional record of June and July
rainfall, mean summer PDSI, and August and
September stream flow. Therefore, we consider the
NEO chronology as a record of warm season
precipitation and drought from 1650 to 2005.
Decades of decreased precipitation occurred in
the early 1800s about the same time of settlement
in the region and of a cooling that is
well-documented for the Northern Hemisphere
(Briffa et al., 2002). A raw ring width plot of
the composite 409 living series reveals a
significant increase in growth following the
early 1800s (intercorrelation of 0.549). A
comparison of raw ring widths between living
trees (n233 total time span 1605-2006 AD) and
historical samples (n179 total time span
1550-1891 AD) shows that the increase in growth
is found solely in the living trees as the
historical samples show a more expected
(biologically and geometrically) decrease in
growth with age. This step change in growth in
the living trees may partly be the result of a
reduction in competition after selective logging.
The early decades of the 1800s are an interval of
major changes across the study region in the form
of conversion of forests to agriculture and
selective logging. This frequency rise in
living trees is evident and we cannot rule out
the potential fertilization effect of nearby
agriculture fields that surrounds many of the
living tree sites or the possible high nitrogen
fallout and fertilization from coal burning in
the region over the past century. Some of this
change in growth may be the result of exogenous
factors like climate change or elevated CO2. A
similar observation in increasing raw ring widths
of white and chestnut oaks has been found over
much of the eastern U.S. (Pederson, 2005).

• Conclusions
• This continuing work has extended tree-ring
  chronologies from Northeastern Ohio spanning from
  1550-2006. This suggests the possibility of
  further regional extension in NEO.
• The Midwestern climate changes can be better
  revealed by analyzing these proxies with records
  of meteorological events from the area.
• Narrow rings in this record correlate with
  large-scale volcanic events suggesting regional
  cool summers or Midwest drought associated with
  this cooling.
• Rings prior to the early 1800s show a decrease
  in ring width as they age, while rings after this
  period leading up to the present are widening.
  This maybe due to the increase in CO2,

BACKGROUND AND LOCATION OF SITES The annual
tree-ring widths from crossdated sites forms a
regional chronology spanning 456-years extending
as far back as 1550 with fewer than 10 rings. The
NEO Regional master chronology has been formed
from 26 sites which produced 409 of series from
old-growth structural site series. Sites were
initially concentrated in Wayne County and the
positive correlation between these locations
allowed consideration of sites in neighboring
counties. The NEO chronology (Fig. 2) reveals an
ever-widening climatic region, constantly
increasing replication of annual ring-growth,
climatic signals, and reoccurring pointer
years.
References -Briffa, K. R., T. J. Osborn, F. H.
Schweingruber., P. D. Jones, S. G. Shiyatov, and
E. A. Vaganov, 2002, Tree-ring width and density
data around the Northern Hemisphere Part 2,
spatio-temporal variability and associated
climate patterns. The Holocene 12(6)759-789.
-Cook, E.R. and P.J. Krusic, 2004, North
American Summer PDSI Reconstructions. IGBP
PAGES/World Data Center for Paleoclimatology Data
Contribution Series 2004-045. NOAA/NGDC
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Kairiukstis. 1990. Methods of Dendrochronology.
Dordrecht Kluwer Academic Publishers. 394
p. -Grissino-Mayer, H. D., 2001, Evaluating
crossdating accuracy a manual and tutorial for
the computer program COFECHA. Tree-Ring Research
57205-221. -Mosley-Thompson, E., T. A.,
Mashiotta, L. G., Thompson, 2003, High resolution
ice core records of late Holocene volcanism
current and future contributions from the
Greenland PARCA cores. Volcanism and the Earths
Atmosphere Geophysical Monograph
139153-164. -Pederson, N. 2005, Climatic
Sensitivity and Growth of Southern Temperate
Trees in the Eastern US Implications for the
Carbon Cycle. Ph.D. Thesis. Columbia
University, New York, NY. Pederson, N. E. R.
Cook, G. C. Jacoby, D. M. Peteet, K. L. Griffin.,
2004, The influence of winter temperatures on the
annual radial growth of six northern-range-margin
tree species. Dendrochronologia 227-29. -Stokes,
M. A. and Smiley, T. L., 1968, An introduction to
tree-ring dating Tucson University of Arizona
Press. -http//www.ncdc.noaa.gov/paleo/pdsi.htm
Acknowledgements This work was supported in part
by the Environmental Analysis and Action Program
(EAA) at the College of Wooster funded by the
Henry Luce Foundation as well as funding from Ed
Cook. We thank The Wilderness Center in Wilmot,
the Ohio Department of Natural Resources, The
Nature Conservancy, Shawn Godwin, Paul Locher,
Wayne College, Dave Taggart, and Susan Burt for
permission to sample living trees and historical
structures.