Where does girth collide?

In graph theory the girth of a graph is the length (the number of edges) of its shortest cycle. A graph with no cycle at all, such as a tree or forest, has infinite (undefined) girth, while a triangle gives girth three; girth constrains structure, bounding how many edges or what colourings a graph can have. The referent is a purely combinatorial invariant of a network, with no physical circumference or strap in sight, joined to the other meanings only by the inherited word for 'going around'.[1]

Unit

The number of edges in the shortest cycle of a graph

Recovery means

Not applicable

Measured by

Determined as the minimum cycle length; graphs containing no cycle are assigned infinite girth

In forest mensuration the girth is the circumference of a tree's stem, conventionally measured at breast height (girth at breast height, GBH) with a girth tape, and readily converted to diameter, basal area, and, with height, to stem volume and biomass. It is one of the oldest field measurements in forestry because it is cheap, repeatable, and strongly predictive of tree size. The referent is a physical circumference of wood, unrelated to a saddle strap or a combinatorial cycle length beyond the shared name.[2]

Unit

The stem circumference, typically at breast height, in centimetres

Recovery means

Not applicable

Measured by

Measured with a girth or diameter tape at breast height and converted to diameter and basal area