A hemlock
keeps time
This tree laid down its first ring in 1559, the year Elizabeth I was crowned. Core COK021 carries 467 of them. Liam Stiefel gave every ring a note — wide rings high, narrow rings low — and four and a half centuries play out over four and a quarter minutes.
What you're hearing
The track is the measurement, not an impression of it. Each ring on the core drives exactly one note, in order, from the pith outward. Nothing is smoothed and nothing is arranged.
Carries ring width, and carries it directly: width sets frequency on a straight line, from 90 hertz at the narrowest ring the tree ever laid down to 255 hertz at the widest. Nothing is rounded to a musical scale, so every distinct width in the core has a pitch of its own — a hundredth of a millimetre is a note you can tell apart.
Fixed at 0.55 seconds per ring. Every year gets identical time, so the ear compares like with like.
467 notes, four minutes and sixteen seconds, no edits. Nothing is repeated and nothing is left out.
The specimen
Taken with an increment borer, which removes a straw-width cylinder of wood and leaves the tree standing.
- Sample
- COK021
- Species
- Eastern hemlock, Tsuga canadensis
- Location
- Unlisted · Highlands, North Carolina
- Rings on the core
- 467
- First ring
- 1559
- Last ring
- 2025
- Standing age
- At least 467 years
- Ring widths
- 0.16 mm to 1.14 mm
- Rings in this recording
- 467 — the complete rings, 1559 to 2025
- Recording length
- 4 min 16 s, one note per ring
- Coring, measurement, sound
- Liam Stiefel
A core is taken at chest height, so the count begins where the borer went in — not where the seed landed. Eastern hemlock seedlings can hold in deep shade for decades before they clear a meter. Four hundred and sixty-seven is the number we can document. The tree is almost certainly older.
We are not publishing where it stands. A tree that has gone unnoticed for four and a half centuries has done well out of being left alone, and the soil over its roots compacts easily. The recording is the part worth sharing.
What the core says
Four passages you can pick out by ear.
The open years. Growth sits near the top of the range and stays there for more than a century, averaging close to three-quarters of a millimetre a year against four-tenths for the core as a whole. The widest ring on the core, in 1595, belongs to this stretch — this tree had light, and used it.
The step down. The sharpest sustained drop anywhere on the core: growth roughly halves within a few years and never returns to what it was. Something closed over it.
The quiet stretch. More than a century of the narrowest wood on the core, averaging a little over two-tenths of a millimetre a year. The thinnest ring the tree ever laid down sits here, in 1890 — the single lowest note in the recording.
The release. Growth almost doubles in a single year — the 2007 ring is the widest the tree has put on since 1679 — and it has stayed high ever since, wider on average than any stretch since the 1740s. This is not the tree recovering. The hemlock woolly adelgid reached these mountains in the early 2000s and killed the hemlocks standing around this one. What the last twenty seconds record is light arriving through the gaps where its neighbours used to be.
About the project
Liam Stiefel built this at the Station: the coring, the ring measurements, and the software that turns width into pitch. The idea is simple and slightly unfair to the tree — four and a half centuries of patient, unhurried record-keeping, compressed into something you can take in before your coffee goes cold.
COK021 is the oldest hemlock we have measured, and it is not a record. The Eastern OLDLIST, which tracks maximum documented ages for the species, tops out at 555 years for a crossdated tree at Tionesta, Pennsylvania, followed by 550 at Schall's Gap and 540 on the Presque Isle River in Michigan. At 467 this core would sit ninth on that list.
What it would be is the oldest eastern hemlock yet documented in the Southern Appalachians. The oldest entry from this region is 389 years, a ring-counted tree at Ramsay Branch in the Great Smoky Mountains. That is a gap of nearly eighty years — which says less about this tree than about how few of them have been aged before the adelgid got to them.
The last passage is the hardest to hear once you know what it is. The tree is growing faster now than it has in three centuries, and the reason is that the hemlocks around it are dead.
More cores are being read now. Each one becomes another track, and together they will make a chorus of the oldest trees we have found, recorded while those trees are still standing.
Hear the next one
New cores, new tracks, and the rest of what happens here — sent when there is something worth sending.
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The Highlands Biological Station funds the research, the equipment, and the students who do this kind of listening.
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