Start with the dating question
Radiocarbon measures remaining carbon-14 in once-living material. Dendrochronology matches tree-ring patterns and, when the sequence reaches the bark edge and a master chronology, may constrain a felling date. Neither method automatically dates construction, deposition, use or destruction.
Sample
Material, species or tissue, pretreatment, mass and sampled location.
Measurement
Laboratory identifier, conventional age or ring sequence, uncertainty and quality notes.
Interpretation
Association with the event of interest, residuality, reuse and contamination.
Radiocarbon ages require calibration
A conventional radiocarbon age is not a calendar date. Calibration compares the measurement and uncertainty with an internationally maintained curve. Because the curve has plateaus and reversals, one result can produce several calendar ranges. Report the curve version, software, probability range and any reservoir correction.
Old wood and reservoir effects
Heartwood can predate felling by decades or centuries. Marine and freshwater organisms may incorporate carbon with a different apparent age. Conservation materials, consolidants and soil carbon can contaminate a sample. Pretreatment reduces some risks but does not repair a poor contextual association.
Evidence exercise
A roof timber yields an outer surviving ring date of 1218 CE, but sapwood and bark are absent. Write the supported claim and the unsupported claim. Supported: the preserved outer ring formed in 1218. Unsupported: the tree was felled, or the roof built, in 1218.
Record before comparing
- Object and context identifier; sampling permission and whether sampling was destructive.
- Material identification, sampled position and pretreatment.
- Laboratory code, result, uncertainty, calibration curve and software version.
- Contextual relationship, reuse risk and the event actually being dated.
Sources
Sources accessed 10 October 2026. This page provides no dates for an unidentified object and no sampling authorization.
Radiocarbon and Tree-Ring Dating
A laboratory result dates sampled material. Archaeological interpretation must still connect that sample to an object, event and context.
| Observe | Describe material, form, marks, wear or spatial relation without assigning identity or purpose. Begin with “Start with the dating question.” |
|---|---|
| Context | Locate the record in excavation, collection, restoration and display history. Check the chain against Reimer et al. (2020), IntCal20 calibration curve and Historic England: Dendrochronology guidelines. |
| Infer | A laboratory date belongs to a sampled material and a calibrated probability range, not automatically to the event a historian hopes to date. Tie every attribution to the feature that supports it and retain competing readings. |
| Withhold | Do not extend “Sample” beyond the date, sample, comparison or provenance actually documented. |
Provenance checkpoint
List each custody or documentation gap separately; an unknown interval is evidence about the record, not permission to invent continuity.
Catalogue note
Radiocarbon measures remaining carbon-14 in once-living material. Dendrochronology matches tree-ring patterns and, when the sequence reaches the bark edge and a master chronology, may constrain a felling date. Mark later repairs, labels and digital reconstructions as later interventions rather than original features.
Research-room promptWhat single comparison object, technical test or archive entry would most change the interpretation of Radiocarbon and Tree-Ring Dating?