Tree Allometrics

Equations / Stem volume

Generic stem volume from Dbh (Lama forest)

Stem volumeEighteen dominant tree species of Lama forest plus species from Guendehou et al. (2012)BeninnaturalRead from the original paper
Many species, no single photo
Equation

As printed (Eq. 3 and 5, p. 7; Table 3 (Model structure: ln(V) = x0 + x1ln(Dbh)), p. 9)

Generic –1.48*** (0.04) 2.29*** (0.01) 97.51 32 0.05 615

In this library's units, ready to compute (m³)

Stem volume = 0.001 * exp(-1.48 + 2.29 * ln(D) + 0.05)
D
Diameter at breast height (1.3 m), cm

Total stem volume (stem = height to crown base), not whole-tree volume. Paper unit is 10^-3 m3 (= dm3); canonical expression converts to m3. Coefficients are printed to 2 decimals, so predictions are only as precise as that. σ²/2 is the paper's printed bias-correction term, added inside the exponent (Eq. 5); it is printed rounded to 2 decimals. Adjusted R² 97.51%, rRMSE 32% (Table 3). Fitted on 617 trees (this study plus Guendehou et al. 2012).

Source
This resulted in 617 trees used for the generic volume and biomass models.
Trees measured · Section 2.3, p. 7
Trees measured
617
Method
ln-ln linear regression, back-transformed with exp(σ²/2) (printed σ²/2 is rounded to 2 decimals)
Where
Lama forest reserve, southern Benin (semi-deciduous forest)
Last checked
2026-11-02
Calculate
0.228
Stem volume (m³)
00.20.40.60.811.2510152025303540DBH (cm)Stem volume (m³)Stem volume

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 = 200.2280.228Computed from the printed form
computed from the published form (coefficients as printed to 2 decimals)
D = 401.121.12Computed from the printed form
computed from the published form (coefficients as printed to 2 decimals)

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