A dendrochronologist is a scientist who dates historic timber structures and artefacts by analysing the pattern of annual growth rings in wood. Each year a tree grows a new ring whose width is influenced by the climate conditions of that year; by comparing the ring pattern in a sample to master chronologies built up from thousands of overlapping samples, scientists can pinpoint the year - and sometimes the season - in which a tree was felled. This technique has revolutionised the dating of medieval buildings in the UK and is increasingly required as part of conservation management plans and heritage assessments for significant historic structures.
What they do
- Take core or wedge samples from historic timber structures
- Measure and analyse annual ring patterns in samples
- Compare samples against British and European master chronologies
- Identify felling dates for original and reused timbers
- Produce dated building reports for heritage and planning purposes
- Advise on the significance and phasing of building development
- Provide expert witness reports on dating questions
- Contribute to architectural history research programmes
When you need one
A dendrochronologist is needed when the construction date of a historic timber building needs to be established scientifically - for conservation, listing, research or insurance purposes.
Typical costs (UK, 2025)
| Job type | Typical cost |
|---|---|
| Single building dendrochronology study | £1,500 - £4,000 |
| Sampling and analysis (per sample) | £100 - £200 |
| Full report and archive | £500 - £1,500 |
| Expert witness report | £800 - £3,000 |
| Research consultation | £100 - £180 / hr |
The number of samples needed depends on the complexity of the building and how many construction phases are suspected. A preliminary assessment visit may be needed before quoting. Travel costs apply for sites outside the specialist's area.
Qualifications to look for
Historic England recognises and works with established dendrochronology laboratories. The key practitioners in the UK operate from university-based or specialist units with a track record of published dating work. Ask for a list of previous projects and check whether their results have been deposited in the National Dendrochronology Database.
Many dendrochronologists hold CIfA membership as they work alongside archaeologists on building recording projects. MCIfA or ACIfA membership indicates professional standards in recording, reporting and archiving.
How to find a dendrochronologist
Frequently asked questions
How does dendrochronology work?
Trees grow a new ring each year - the width of each ring varies with the climate conditions that year, creating a unique pattern. A timber sample is compared to a master chronology (reference sequence) built up from many overlapping samples to find a matching position and thus the year the tree was felled. British master chronologies now extend back over 7,000 years.
How accurate is dendrochronology?
Highly accurate - it can often pinpoint the felling date to a specific year, and sometimes to the season (winter or spring felling), based on the presence or absence of a sapwood layer at the outer edge of the timber. The technique has transformed understanding of the construction dates of medieval buildings, allowing correction of many dates previously estimated from architectural style alone.
What buildings can be dated by dendrochronology?
Any historic building with in-situ original timber can potentially be dated - medieval hall houses, oak frame barns, church roofs, historic ships and furniture. Success depends on the number of rings in the sample (a minimum of around 50 rings is needed for reliable dating) and the existence of a matching master chronology for the region. Replacement timbers cannot be used to date the original construction.