Annual Ring
Definition
A single year's growth increment visible as a concentric band in a transverse wood section. In most temperate trees, each ring consists of a lighter early-wood (spring growth, wider cells) and a darker late-wood (summer-autumn growth, smaller cells with thicker walls).
- Formed by
- One growing season (early-wood plus late-wood)
- Early-wood
- Wider, thinner-walled cells, lighter colour
- Late-wood
- Narrower, thicker-walled cells, darker colour
- Used in
- Dendrochronology, timber dating, growth-rate estimation
Common questions
Can a single tree grow more than one ring in a year?+
Yes. A false ring can form after a mid-season stress event such as drought or defoliation followed by renewed growth, and cross-dating against a reference chronology is needed to tell a false ring from a true annual boundary.
Why do forensic examiners count rings on stolen or trafficked timber?+
The ring count and pattern give a felling year and, when matched against a regional chronology, a growth location, which supports cases on illegal logging, protected-species timber and cross-border trafficking.
Related terms
- Crossdating
- The matching of ring-width patterns between two or more samples to determine their relative or absolute temporal relationship. The master method of...
- Floating Chronology
- A ring-width sequence whose pattern is internally consistent but whose absolute calendar position is unknown because it cannot yet be crossdated to...
- Master Chronology
- A continuous, absolutely dated ring-width sequence built by overlapping many individual samples, living trees linked to old timbers and subfossil wood. Regional...
- Missing Ring
- A year in which growth was so suppressed, by extreme drought, frost, or injury, that no visible ring was deposited. Missing rings...
- Sapwood
- The outer living wood of a tree, typically lighter in colour than the dark heartwood. Species have characteristic sapwood ring counts (a...