BrVQ
BraVSQ Oak Chronology for the region Västra Götaland by Alf Bråthen. It was originally published in the book: Alf Bråthen: Dendrokronologisk serie från västra Sverige 831-1975. Rapport RAÄ 1982:1. ISBN 91-7192-511-2. The BraVSQ chronology is based in that book only. In an article 1983 Bråthen, makes some corrections and also publish two enlarged and corrected chronologies, called "Block 4" and "Block 5".[1] According to the fact that some samples are used in more than one of the chronologies, and the differences according to samples provenience it may not be a good idea to mix them together. Therefore we may instead prefer the five chronologies "blocks" as they are: BrVQ1, BrVQ2, BrVQ3, BrVQ4, BrVQ5.
In the original book from 1982, four different Chronologies are given, with annual average values and the number of measurements behind each value. There are also detailed documentation about the origins of each sample. The four chronologies are originally named: "Block 1", "Block 2", "Block 2b" and "Block 3". Unfortunately there are some severe errors in the material, which have to be corrected before the chronologies can be used. The wrong date for the Lödöse Chronology was discovered soon after the publication, and a corrected (and enlarged) chronology was published by Bråthen 1983.[1]
Still the material from the first book is very valuable and useful, when mis datings are corrected and bad sequences are removed. The measurements were originally done in 0.1 mm resolution, but the average series are given in 0.01 mm resolution. The regional references published in the supplement 1983 are also valuable, although a disadvantage with those are that they are mixing in material also from Halland. It would have been better if the material from Västergötland/Diocese of Skara had been kept separated from the Halland material. Now we do not have that good local Västergötland/Skara references as we might have had otherwise. The local Halland reference, HallandQU, is now partly based on the same samples as "block 4" and "Block 5".
An analysis of the BraVSQ-material
For the following analysis, I have used four independent oak-chronologies: OlandQUSP, WestDK, BohusRec and HallandQU (see List of references). The documentation and result of this analysis is available at http://www2.hemsida.net/taxelson/dendro/BrathenEk.zip (WebCite).
Block 1
BrVQ1. Recent: 1615-1975. At least 4 samples depth: 1634-1974, 9 contemporary stems as best. No problems found.
Block 2
BrVQ2. Historical: 1337-1804. At least 4 samples depth: 1380-1779, 16 contemporary stems as best. Bråthen 1983 do not reports any problems.[1]. But apart from that, some problems may still persist:
- The period 1554-1613 has almost zero-correlation towards other references, and has to be removed. It is obviously erroneous. The reason for this problem is not yet known.
- Value for 1650 is missing.
Block 2b
Historical: 1197-1490
Block 2b is very problematic[2], which is revealed by a block analysis. It was dated by Bråthen to 1490, and the youngest part is obviously correctly dated, but the older part does not correlate at all to other references at its given position! Instead that older part correlates as if the whole 2b-block should be dated to 1197, i.e the samples in the oldest part are erroneously dated 293 years too late! Samples of two very different ages have been mixed together.
When carefully reading the documentation and constructing the samples positions and lengths these mistakes were revealed: Six samples from Götene and Kungslena churches which are from early 12'th century have been mixed into the chronology at a position 293 years too late. As there is only an average series available, only the early and late ends of Block 2b may be used in a new reference as these "clean ends" are based on one curve and are not created as a mean value mix of incorrectly matched chronology members, i.e 904-974 (misdated as 1197-1267) and 1419-1490.
On page 32-33 is a list of 12 samples which are said to be the samples in the average series "Block2b", but that list is not correct. That is obvious when compared to the number of samples said to be behind each value in the average chronology. The correct list could almost be reconstructed from the complementary list at pp. 90-94 and the years when the number of samples per year are altered in the chronology. It is than revealed that one sample from Hedared is forgotten in the first list and that one sample from Götene church is confused i the table.
| Id | Bråthen's id | Description | use | Correct dating (used part) |
|---|---|---|---|---|
| Ba1 | Bälinge 1 | 1436-1314 | yes | yes |
| Ba2 | Bälinge S. remstycke | 1482-1313 | yes | yes |
| Ba3 | Bälinge N. remstycke | 1506-1280 | 1490-1280 | yes |
| Go1 | Götene 1 | 1418-1213 | yes | 1125-920[3] |
| Go3 | Götene 3 | 1396-1239 | yes | 1103-946 |
| Go4 | Götene 4 | 1301-1157 | 1301-1197 | 1008-864 (-904) |
| Go5 | Götene 5 | 1383-1198[4] | yes | 1090-905 |
| He1 | Hedared 1 | 1487-1338 | yes | yes |
| He3 | Hedared 3[5] | 1426-1268 | 1426-1302[6] | yes |
| He4 | Hedared 4 | 1455-1327 | yes | yes |
| He5 | Hedared 5 | 1488-1346 | yes | yes |
| Ku1 | Kungslena 1 | 1401-1268 | yes | 1108-975[7] |
| Ku2 | Kungslena 2 | 1393-1227 | yes | 1100-934 |
In a book 1995 Bråthen is obviously aware of the correct datings for Götene church (1125) and Kungslena church (1118-1122).[8]
Block 3
BrVQ3. Lödöse, archeological: 780-1298 (Originally mis-dated to 831-1349). At least 4 samples depth: 867-1185. As best: 19. No other problems found.
Block 4
BrVQ4. This chronology is mainly based on buildings in the Diocese of Skara, but also some samples from Lindberg in Halland is included. Some of the Lindberg samples may also be included in HallandQ. The chronology is published in the supplement 1983.[1]
Block 5
BrVQ5. This chronology contains the Lödöse material from "Block 3", but also a lot of other material from an extended region including Diocese of Skara and Halland (Halmstad). Some of the material from Halland used in this chronology, is also included in HallandQU. The chronology is published in the supplement 1983.[1]
Downloads
- The five useful "blocks" is available in digitalized form (WebCite: archive)
- Two weighted chronologies of correct and corrected blocks (based on the book from 1982) are present is available. In BVSQgt4 all parts with less than four samples depth is removed.
Notes
- ↑ 1.0 1.1 1.2 1.3 1.4 Alf Bråthen: The tree-ring chronology of Western Sweden 753-1720 in: Dendrokronologiska Sällskapet: Meddelanden 6, 1983.
- ↑ 1983, Bråthen writes about this "block 2b" that it is now "superseded"
- ↑ At p.102 Bråthen remarks that there are Earlywood only for the year 1418. According to the missdating this is to be interpreted as summer (june) 1125! He also remarks that Prof. Erik Lundberg, in a paper 1968, dated the church to 12' century. Lundberg was right! (The correct dating (1125) is noted in Bebyggelseregistret)
- ↑ See p.91 (erroneously 1488-1346 in main table)
- ↑ Not in list, but according to p.91, and as the youngest year corresponds with an altering of the annual number of samples.
- ↑ It may also possibly continue backwards in all its length. There are several possibilities which sample is the truncated one: It may be He3 or Go4 (young end) or Ku1 (old end).
- ↑ The logs from Kungslena church are cut after 1108 and not after 1401.
- ↑ Alf Bråthen: Dated wood from Gotland and the diocese of Skara, Forlaget Hikuin, 1995, p. 92, ISBN 87-87270-75-7