International Tree-ring Data Bank: treering.readme file
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     World Data Center for Paleoclimatology, Boulder
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NOTE: PLEASE CITE ORIGINAL CONTRIBUTOR WHEN USING THIS DATA!!!!!

CONTRIBUTORS:  Numerous ITRDB Members
Please see the file VERSION which contains updates history.
NAME OF DATA SET:  International Tree-ring Data Bank
LAST UPDATE:  12/2015 (Version 7.10).  
More recent contributions can be found in the directory /paleo/treering/updates
GEOGRAPHIC REGION: Global
PERIOD OF RECORD: 2015 A.D.  - 6000 B.C.
LIST OF FILES: Readme.treering.txt (this file), 
Treeinfo.txt (information on methodology and file formats), 
Version.txt (update history of the ITRDB), 
*.rwl files (files of ring measurements in directory /measurements/), 
*.crn files( files of site chronologies in directory /chronologies/),

SUGGESTED DATA CITATION: 
Please cite original publication, online resource and date accessed when using this data. 
If there is no publication information, please cite investigator, title, online resource, 
and date accessed.

DESCRIPTION:
This data set contains tree-ring chronologies and measurements of 
the International Tree-Ring Data Bank and NCEI Paleoclimate Program 
data base.  The chronology and measurement files are ASCII text files, 
and a description of the ITRDB file format can be found in the file TREEINFO.TXT.  
The file VERSION.TXT gives a history of updates to the database. 

Measurements of the widths of the annual rings, or of wood density 
within the annual ring, are recorded in the *.rwl data files.  
The raw ring width data for one site are standardized and the 
results are summed into a site chronology.  The standardization 
process involves fitting a curve to the ringwidth series, and 
then dividing each ringwidth value by the corresponding curve value.
This process allows samples with large differences in growth rates
to be combined, and can be used to remove any undesired growth 
trends present.  The index values are unitless, with a nearly 
stable mean and variance, allowing indices from numerous trees to
be averaged into a site chronology.  The chronology represents the 
departure of growth for a given year vs the series mean, and is 
expressed as a 4 digit integer with 1000 representing the long term 
mean. 

References:

Grissino-Mayer, H.D., and Fritts, H.C. 1997. The International Tree-Ring
Data Bank: an enhanced global database serving the global scientific
community.  The Holocene 7,2  pp. 235-238.

Cook, E.R., and Kairiukstis, L.A., eds. 1990.  Methods of 
Dendrochronology.  Kluwer Academic Publishers, 101 Philip Drive, 
Norwell, MA 02061 USA, or P.O. Box 17, 3300 AA Dordrecht, The 
Netherlands.

Fritts, H. C. 1976.  Tree Rings and Climate.  Academic Press LTD., 
24/28 Oval Road, London NW1, or 111 Fifth Avenue, New York NY 
10003.

Hughes, M.K. et al. 1982.  Climate from Tree Rings.   Cambridge 
University Press, Cambridge, UK.