Tree Allometrics

Equations / Stem biomass

Stem biomass, 18-year secondary montane forest, DAP² only

Stem biomassSecondary montane forest trees, mixed speciesEcuadornaturalRead from the original paper
Many species, no single photo
Equation

As printed (Tabla 4, p. 88 (fuste, 18-year))

Bf = e^(9,156 + 1,354*ln(Dap²))

In this library's units, ready to compute (kg)

Stem biomass = exp(9.156 + 1.354 * ln((D/100)^2))
D
Diameter at breast height (1.3 m), cm

Dap is in metres in the paper (Tabla 4 footnote), Ht in m, biomass in kg; printed as e^(a + b*ln(...)), natural log, no correction factor stated. Per-model adjusted R2 is in Tabla 4 but it is adjusted R2 and the per-model n is not stated, so both left out. Total = stem + branches + leaves. Stand age approx. (owner information).

Source
Method
regression on ln-transformed variables; coefficients as printed
Where
Cotacachi, Imbabura, NW Ecuador (1850 m a.s.l.)
Last checked
2026-11-02
Calculate
18.55
Stem biomass (kg)
8.72
Carbon (kg), ×0.47
31.97
CO₂e (kg), ×44/12
0200400600800510152025303540DBH (cm)Stem biomass (kg)Stem biomass

Shaded: the DBH range the model was fitted on. Other inputs held at the values above.

Checks this equation passes

On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.

InputsExpectedWe getFrom
D = 1018.618.6Computed from the printed form
hand-computed from the published form (Dap in m)
D = 25221.8221.8Computed from the printed form
hand-computed from the published form (Dap in m)

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