Timber calliper

A timber calliper measures the diameter of standing trees or felled logs. It may be made of wood or metal. Diameter is the distance across the trunk, not its circumference.

Different constructions

Fixed wooden callipers could be H-shaped, with a different opening on each side. Such a tool does not necessarily have moving parts. A sliding diameter calliper has a graduated beam with one fixed arm and another moving along it. Other designs also exist. Describe the actual construction rather than treating every forestry calliper as the same model.

Examining an older example

Photograph the complete scale, arms, joints and any maker's marks. Record the measurement unit actually visible. Drying, wear and damage should be noted as condition issues; accuracy should not be promised without checking. Numbers on the tool are not automatically dates. Also distinguish a diameter reading from any separate tables or scales intended to indicate volume or price.

Sources: Audun Dybdahl, SNL: Tømmerklave; SNL: Diameterklave, fagkonsulent Hans Fredrik Hoen.