5. Decadal files

The Decadal .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 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.

CDendro now 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.

Exercise:
Open your collection file "fourfiles.fil" and write it back as a Decadal 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".

Selecting a sample from a decadal file:

Click on Samples on the menu bar. Then click on "Select from decadal file"

Open the decadal file "fourfiles.rwl" which you saved a moment ago.

Click on one of the sample members in the decadal file and click Extract (or double-click on the member).

A normal type of sample window will pop up. Close the window for selecting from the decadal file by clicking on Exit.

You can save the extracted data as either
a decadal file with only one member (as .rwl or as .fh),
a ring width file (.wid) or
a normalized file (.d12)
Just click on "Samples" on the menu bar and select the proper alternative from the drop down menu.

Note: 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.

Opening a big decadal file as your reference

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 decadal file fourfiles.rwl

Note1: Detrending options for this command can be set at Settings/More settings.

Note2 - what is detrending? Normally a young tree grows with wider ring widths than an old tree. If you plot a ring width curve for a tree, the curve is normally highest for the time when tree was young. When calculating mean value of ring width for a specific year (e.g. 1980) for several trees, then the calculation is normally based on trees which were of different age that very year. The youngest trees have wide ring widths, the oldest quite thin ring widths. Detrending is the mathematical process of compensating for this ring width dependence on tree age. With the curve matching algorithms used in CDendro, detrending will only influence on the shape of the calculated mean ring width curve, i.e. that shown in the lower part of the diagrams. Calculated correlation coefficients in CDendro are not depending on the detrending method used.

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 a decadal file had created the sum from the corresponding collection file.

Now select the other window containing that sample you have earlier extracted from this same decadal file.

Click on the button "Make corr. analysis". The reference curve will immediatly pop up at that position where the highest correlation value was found.
If you click on the Workbench tab you can see the normal text report.

Note: Another way to extract samples from a decadal file is to use Create new collection from decadal file That command creates a collection with a member for each sample in the decadal file. If you then double-click on a member it will open in a new window. This is normally a better way to extract samples from a decadal file than using the Samples/Select from decadal file menu command.

Decadal file formats - some comments

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