5. Decadal files

Last update July 4 2019/LÅL

The Decadal/Tucson .rwl format is used when storing files into the ITRDB International Tree Ring Data Bank at the University of Arizona. Files stored in this format look like this:

NM051   1757   171   114    68
NM051   1760    80   124   214   189   170   103   154   104   130   131
NM051   1770   143   163   324   467   219   147   124   108   140   117
.....
NM051   1980   123    97    85   110   106    94    94    89   135   110
NM051   1990    72   106    98    93   123   173   999
Nmbs01  1791    60    34    39    22    20    43    67    56   141
Nmbs01  1800   260   256   440   419   268   275   272   275   174   229
....
Nmbs01  1870   110   137   114    98   148   152   999
nmbs05  1773   451   409   385   388   295   339   273
nmbs05  1780   166    65   373   319   407   339   369   437   246   271
...
nmbs05  1870    80   153   103    71    92   137   999
nmbs08  1753   434   230   294   477   257   202   238
nmbs08  1760   250   274   290   163   154   182   241   343   229   364
...
nmbs08  1860   104    85    82    73    99   141   147   135   127   209
nmbs08  1870    96   141    99   999

To the left there is a sample identification, i.e. more than one sample can be stored in the same file.
The second column contains a year number. Then follows up to 10 ring width values in units of 0.01 millimeters.

Note on sample identity length: Sample identities (e.g. NM051) stored in a Tucson decadal file (.rwl or .dec) can never be longer than 8 characters! If a sample contains data covering the time before BC 1000 its identity can not be longer than 7 characters. The ITRDB specification states that the maximum length is only six characters, though many published data files have longer identities.

Note on .rwl (Tucon) file measurement unit: .rwl files can also be written in units of 0.001 millimeters, see CDendro/More Settings/Decadal file measurement units.

CDendro also supports writing of Heidelberg decadal format - these files have extension ".fh". This format is often used for publications as it is a bit more slim and clean than the .rwl format.

HEADER:
KeyCode=NM051
Length=239
DateEnd=1995
DATA:Tree
   171   114    68    80   124   214   189   170   103   154
   104   130   131   143   163   324   467   219   147   124
   108   140   117    88    65    87    62   105    96   120
.....
    89   135   110    72   106    98    93   123   173     0

HEADER:
KeyCode=NMBS01
Length=85
DateEnd=1875
DATA:Tree
    60    34    39    22    20    43    67    56   141   260
   256   440   419   268   275   272   275   174   229   254
....
   137   114    98   148   152     0     0     0     0     0

HEADER:
KeyCode=NMBS05
....

You can save data from a collection in a decadal file as a .rwl or a .fh file

You can also create a reference curve from a big Decadal file. I.e. you can create a normalized meanvalue file from a .rwl or .fh file. This can be done in two ways:
Either select the command Collections/Create reference curve from big decadalfile (for detrending and sum-by-stem usage see Settings/More settings)
or open the collection and then click the button "Create Mean value sample".

Exercise:
Open your collection file "fourfiles.fil" and write it back as a Tucson decadal/.rwl file. Save it as "fourfiles.rwl".
Close the collection file.
Note: If you have not dated your collection file, you will not be able to save it as a Decadal file. This is because the Decadal file format demands a dating year for each ring width.

Note: Earlier versions of CDendro used the ".dec" extension for decadal file names. The default extension today is ".rwl" to make CDendro more compatible with data from other programs. Decadal files from the ITRDB are always named with the ".rwl" extension. Anyhow, CDendro will make no difference if your file names end with ".rwl" or with ".dec".

How to open a sample from within a decadal file?

First open the collection file.
Then double-click that member you want to open as a separate sample file.

Exercise: Opening a big decadal file as your reference and make a crossdate

One way to open up a big reference curve is to open the corresponding decadal file.

Click on "Collections/Create reference curve from big decadal file" and select the Tucson decadal file fourfiles.rwl

Note: Detrending options for this command can be set at Settings/More settings.

A new window with a summed decadal file has been opened. Click the Workbench tab to inspect the amount of data behind this mean value sample!
The table above shows the number of ring widths covering each year of the mean value sample created out of the collection.

See that this sample-window is selected as the reference!
Click on the Curve display tab to inspect the curves!

Scroll the curves window some 100 years and your screen will look as above.
This is the same curves you would have seen if you instead of using the menu command "Collections/Create reference curve from big decadalfile" had created the sum from the corresponding collection file with the collection button "Create mean value sample".

Note: If your curve does not look as above, check your setting for Settings/Plotting window settings/Plot curves with old times towards right.

Now open the Namdo.rwl collection by using the command Collections/Open menu for collections.../Open Tucson .rwl collection. Then double-click on the member with MemberID "6674".

This sample is already correctly dated within the Namdo.rwl collection, so it will pop-up at its right place in relation to the reference created from fourfiles.rwl. As all members of fourfiles.rwl and of Namdo.rwl come from the island of Nämdö or near to this island we will here see a proper match - notice the correlation values 0.76/9.3 (corrCoef/TTest) at the bottom of the diagram above!

Now click on the Workbench tab and then click the button "Make a whole sample correlation analysis" (corresponds to the button "Make corr. analysis" on the Curve display) to get the following report.

6674_of_F:\Program Files\Cybis\CDendro76\demo\Namdo.rwl using No detrend
compared to the reference
F:\Program Files\Cybis\CDendro76\demo\fourfiles of length 243 using No detrend  Dated to 1995
Minimum overlap used when finding best match: 50

Table sorted by Mean of sliding frame algorithms (2,0,T (MeanSF)/CorrC

--Rel Over   P2Yrs------  BaPi-------  C84F-------  BesIE------  Skel-  GLK-- *MeanSF-----  (year)
-year  lap   CorrC TTest  CorrC TTest  CorrC TTest  CorrC TTest   Chi2    GLK  CorrC TTest
  133   67    0.79  10.4   0.74   8.8   0.75   9.1   0.75   9.1   12.8   0.75   0.76   9.3  (1862) (as dated)
   -4   63    0.33   2.8   0.38   3.2   0.36   3.0   0.22   1.7    0.9   0.56   0.32   2.7  (1999)
   11   67    0.26   2.2   0.34   2.9   0.36   3.1   0.26   2.2    3.2   0.52   0.30   2.6  (1984)
   92   67    0.27   2.3   0.27   2.3   0.33   2.8   0.27   2.3    0.7   0.59   0.29   2.4  (1903)
   81   67    0.38   3.3   0.27   2.3   0.28   2.4   0.19   1.5    4.4   0.60   0.28   2.4  (1914)
   75   67    0.30   2.6   0.29   2.4   0.30   2.5   0.22   1.9    1.0   0.59   0.28   2.3  (1920)
   83   67    0.32   2.7   0.22   1.8   0.26   2.1   0.32   2.7    4.4   0.62   0.28   2.3  (1912)
  188   52    0.32   2.4   0.30   2.3   0.26   1.9   0.18   1.3    5.1   0.62   0.26   1.9  (1807)
   98   67    0.26   2.2   0.25   2.0   0.28   2.4   0.25   2.1    0.4   0.55   0.26   2.2  (1897)

Decadal file formats - some comments

Keep the file name extension right! If you download a decadal file via FTP from the International Tree Ring Data Bank, the downloaded file is stored with extension .rwl CDendro will read decadal files with extension .dec or .rwl but not as .txt!
If you download through HTTP/Save target as, then the files will be saved with extension .txt if you save them as type Text document, e.g. saved as swed305.rwl.txt You then have to remove the appended ".txt" in the filename. If you save them as type "All Files" the file name will be written without that .txt extension!

Note: Some files at the ITRDB are stored in file formats which are a bit incompatible with normal PC files. If you run into trouble with reading a file from the ITRDB, try to copy its content (Ctrl-C) and paste (Ctrl-V) it into e.g. the Notepad text editor and save the file.

For a more thorough description of various Tucson .rwl formats, see Cybis wiki: Tucson format

There are many variants of the decadal file format.
E.g. special characters, like a dot (.) show up at places you would not predict from what you think is the original specification.
CDendro is able to read most .rwl files stored in the ITRDB, i.e. as soon as we have found a problem. the program has been updated.

I will try to here display some special cases.

Comments on this matter in CDendro code...

ITRDB data from Finland

This is a CORING .rwl file created from .cat-files