Fundamentals
Wood density
Mass per unit volume of wood, the conversion that turns measured volume into biomass.
Two stems of equal volume can differ substantially in mass depending on species. Wood density supplies the bridge, and it is usually drawn from regional databases where direct sampling is impractical.
Using a generic value across a mixed forest is a recognised bias source. Species-weighted or genus-level values, with documented provenance, are the defensible middle ground.
Frequently asked questions
Does density vary within a tree?
Yes. It differs between heartwood, sapwood and height sections, which is why values are reported as averages.
Where do values come from?
Global and regional wood density databases compiled from destructive sampling studies.