# Dendrochronology: The Floor Under a Panel's Date
> Tree rings date the timber, not the picture. The chain from last ring to felling to first brushstroke is a floor decades wide, and reading it as a date is the standard error.
> The Study - 2026-08-02
> Canonical HTML: https://iconotheca.com/study/dendrochronology-baltic-oak-and-the-floor-under-a-date/
## Key points
- For oak from Poland and the southern Baltic the standard sapwood estimate is 9 to 24 rings at 90 per cent confidence, so a last ring of 1606 means a felling date between 1615 and 1630.
- An Antwerp guild ordinance of 11 December 1617 required panel makers to strip out the sapwood, which is why most seventeenth-century Antwerp panels can only yield a terminus post quem.
- A 2025 replication of Peter Klein's 1990s work on two portraits of the young Rembrandt confirmed his dates, found two measurement errors, and left the attribution question exactly where it was.
- The Metropolitan's Christ Appearing to His Mother was redated definitively when its panel was placed at about 1485, some twenty years after Rogier van der Weyden died.
## The ring dates the timber, and the timber is always older than the picture
## The Baltic timber trade built the reference curve; an Antwerp guild rule then blunted it
## Two portraits of Rembrandt: what the wood settled, and what it could not touch
## Where the wood does decide: a board felled after the painter was dead
## The failure modes to ask about before quoting a report
Dendrochronology is the most rigorous dating tool in the technical repertoire and the most frequently overstated. It measures wood. Between the last ring and the painted surface lie a felling range, a sea voyage, a seasoning period and a panel maker's stock, and every one of those intervals runs forward. Used as a filter the method is close to decisive, because no panel can precede its tree. Used as a certificate it is worthless, because a period panel is exactly what a competent copyist, a workshop assistant and a patient forger all have access to. Ask for the rings, the chronology, the overlap and the t value, and read the answer as a floor.
## Questions
**If the panel dates to the artist's lifetime, does that support the attribution?**
It removes an objection rather than supplying evidence. Studio copies, contemporary versions and later pictures painted on reused boards all sit on period wood. In the 2025 Rembrandt replication both the accepted original in Nuremberg and the accepted studio copy in The Hague returned entirely period-consistent panels.
**What does a same-tree match between two panels actually prove?**
That the boards were cut from one log, which normally means they passed through the same panel maker's stock at about the same time. It is strong evidence of a shared workshop supply and of near-contemporary production. It says nothing about who painted either picture: in the Rembrandt case the same-tree partner is catalogued as circle of Rembrandt.
**Why do dendrochronological reports quote a t value?**
It is the Student's t statistic calculated after normalising the ring widths using the algorithm published by Baillie and Pilcher in 1973, and it measures how well the measured series matches a reference chronology at a given position. In the 1980s values above 3.5 over a hundred-ring overlap were accepted as promising; current practice expects above 5, alongside a parallel variation above 63 per cent and a good visual match.
**Can tree rings date a painting on canvas?**
Not the painting. A stretcher or strainer can occasionally be sampled, but stretchers are replaced routinely and the softwoods usually found in them are poorly served by the oak chronologies, so a stretcher date is evidence about the stretcher. For canvas the equivalent structural evidence is the weave, read from the radiograph.
## Sources
- [1] National Gallery of Victoria, Peter Klein, 'A note on dendrochronological analyses of panel paintings at the National Gallery of Victoria' (sapwood statistics, seasoning times, worked examples).
- [2] Marta Dominguez-Delmas, 'A replication study in dendrochronology - revisiting the panels of two portraits of Rembrandt', Humanities and Social Sciences Communications 12, 1778 (2025).
- [3] Andrea Seim et al., 'Timber trade in 17th-century Europe: different wood sources for artworks of Flemish painters', Scientific Reports 14, 18216 (2024).
- [4] Marta Dominguez-Delmas et al., 'X-ray computed tomography for non-invasive dendrochronology reveals a concealed double panelling on a painting from Rubens' studio', PLoS ONE 16(8): e0255792 (2021).
- [5] Paul Jeromack, 'Dendrochronology and infra-red photography are giving surprising results among Netherlandish paintings at the Metropolitan Museum', The Art Newspaper, 31 March 1993 (Ainsworth on Christ Appearing to His Mother).
- [6] Martin Bailey, 'Prado opens landmark Bosch exhibition amid attribution controversy', The Art Newspaper, 31 May 2016 (panel dated 1464; Prado dating 1510-15).
- [7] Walter Liedtke, C. Richard Johnson Jr. and Don H. Johnson, 'Canvas Matches in Vermeer: A Case Study in the Computer Analysis of Fabric Supports', Metropolitan Museum Journal 47 (2012), pp. 101-108.
- [8] Marjorie E. Wieseman, Alexandra Libby, E. Melanie Gifford and Dina Anchin, 'Vermeer's Studio and the Girl with a Flute: New Findings from the National Gallery of Art', Journal of Historians of Netherlandish Art 14:2 (2022).