Equations / Stem biomass
Generic stem biomass from Dbh (Lama forest)
As printed (Eq. 3 and 5, p. 7; Table 4 (Model structure: ln(X) = x0 + x1ln(Dbh)), p. 10)
In this library's units, ready to compute (kg)
Stem biomass = exp(-1.98 + 2.3 * ln(D) + 0.1)D- Diameter at breast height (1.3 m), cm
Stem biomass only (stem = height to crown base); the authors say to multiply by a biomass expansion factor (IPCC 2006) to get aboveground biomass. 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. Fitted on the 501 trees of this study plus those of Guendehou et al. (2012) (617 trees); the paper gives no Dbh range for the combined set, and the authors warn it predicts most species poorly. Adjusted R² 95.07%, rRMSE 45% (Table 4).
doi:10.14214/sf.1474 · Open access · copy we read
This resulted in 617 trees used for the generic volume and biomass models.
- 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
Shaded: the DBH range the model was fitted on. Other inputs held at the values above.
On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.
| Inputs | Expected | We get | From |
|---|---|---|---|
| D = 20 | 150 | 150 | Computed from the printed form computed from the published form (coefficients as printed to 2 decimals) |
| D = 40 | 738 | 738 | Computed from the printed form computed from the published form (coefficients as printed to 2 decimals) |
Related
- Albizia zygia stem biomass from Dbh · same paper · Stem biomass
- Cassipourea congoensis stem biomass from Dbh · same paper · Stem biomass
- Generic stem volume from Dbh (Lama forest) · same paper · Stem volume
- Holoptelea grandis stem biomass from Dbh · same paper · Stem biomass
- Khaya senegalensis stem biomass from Dbh · same paper · Stem biomass
- Terminalia superba stem biomass from Dbh · same paper · Stem biomass
- Triplochiton scleroxylon stem biomass from Dbh · same paper · Stem biomass