Annual ring table

Annual rings of a spruce trunk

A tree ring table or a tree ring calendar is a time series of tree rings of a dendrochronological artificial tree . Because of regional and species-related differences in tree growth, such a table must always refer to a single tree species from the same region. Such a time series is created for each artificial tree of this type in that the width values ​​of the recorded rings from different times are lined up in an overlapping manner.

As long as this dendrochronological artificial tree can be created without gaps, it is possible to classify and date wooden finds on this artificial tree by comparing the characteristic ring spacing , since the fluctuating sequence of the climate leaves a clear pattern of the thickness of the annual rings in the wooden plants. The prerequisite is that the find contains enough annual rings to achieve clarity for the comparison and also comes from the period depicted by the artificial tree.

Some important annual ring tables are listed below:

• the Hohenheim annual ring calendar refers to oaks and pines in Central Europe as artificial trees. It covers a total of 12,483 years (so it extends into the Younger Dryas ); however, the data are not scientifically published (as of 2009)
• the Eastern Mediterranean curve of the " Aegean Dendrochronology Project ", u. a. for oak, extends to 1800 BC BC ( Bronze Age ) (as of 2003)
• Bristle jaw chronology
• the annual ring table from Belfast (Ireland) for oaks extends to 5474 BC Chr. (As of 2006)
• the English standard curve extends to 5012 BC Chr. (As of 2006)
• the Sequoiadendron giganteum chronology for the USA

In April 2013, the Swiss Federal Research Institute for Forests, Snow and Landscape (WSL) in Zurich- Wiedikon was able to recover about 14,000 year old tree stumps from subfossil forests, which could be the oldest surviving remains of a forest in the world. Using the radiocarbon method, ETH Zurich dated three wood samples from the clay layer several meters thick to an age of almost 14,000 years. For the dendrochronology , the finds could possibly allow a dating going back 2000 years on the basis of the annual ring tables.

In September 2006, the journal Science reported that based on ancient kauri trees that were discovered in New Zealand bogs , an annual ring table could be drawn up in the coming years that would go back 50,000 years. These wood finds could also be used to better calibrate the radiocarbon dating .

See also

• chronology
• climatology
• botany

Web links

1. Tree ring research at the Federal Research Institute WSL, Birmensdorf  ( page no longer available )
2. Laboratory of Tree-Ring Research
3. University of Hohenheim, Institute of Botany, Hohenheim tree ring calendar
4. The Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology at Cornell University  ( page no longer available )

Individual evidence

1. ↑ Tages-Anzeiger (May 21, 2013): Hélène Arnet: The oldest forest in the world , accessed on May 22, 2013.
2. ↑ Subfossil forest discovered in Zurich. In: Archeology Online. May 24, 2013, accessed February 10, 2020 . 
3. ^ Radiocarbon Dating's Final Frontier. In: Science . Washington DC 313.2006, No. 5793 (Sept 15), pp. 1560-1564, ISSN  0036-8075 .