Standing Tree Volume & Basal Area Calculator

How it works

Basal area = π × (DBH/2)²; volume = basal area × height × form factor (0.33 cone … 0.55 near-cylinder); plot BA/ha = Σ tree BA ÷ plot area; QMD = √(mean DBH²)

A tree trunk is roughly a cone stretched toward a cylinder, so its volume is the cross-section at breast height times the height times a form factor that expresses how much taper the species and growing conditions produce — around 0.45 for a typical plantation conifer, higher for tall closed-canopy stems, lower for branchy open-grown hardwoods. Foresters use species-specific volume tables built on the same idea. Summing basal areas over a measured plot gives basal area per hectare, the standard measure of stocking that drives thinning decisions: temperate stands are fully stocked around 30–45 m²/ha. Together with average height and form, plot basal area yields a stand volume, and dividing stems by plot area gives density. Board-foot conversions are approximate; log rules applied to the actual logs are more precise.

Worked example

A 45 cm DBH, 26 m conifer with form factor 0.45: basal area 0.159 m², volume 1.86 m³ (66 ft³), roughly 290 bf. The eight-tree tally on a 0.05 ha plot gives 24.8 m²/ha — moderately stocked at 160 stems/ha.

Frequently asked questions