Equations / Aboveground biomass
C. tabularis AGB from D2H (Model 7, bias-corrected)
© A. J. T. Johnsingh · CC BY-SA · iNaturalistAs printed (Results, Allometric models for total aboveground biomass (Model 7, Table 4), p. 208)
In this library's units, ready to compute (kg)
Aboveground biomass = exp(-3.571 + 1.006 * ln(D^2 * H)) * 1.029D- Diameter at breast height (1.3 m), cm
H- Total tree height, m
Adjusted R2 0.960 and RSE 0.243 as printed for Model 7 in Table 4 (RSE is on the log scale). The paper also prints the final back-transformed form as TAGB = 0.028953 × (D2 × H)^1.006 and a bias-corrected 0.029821 × (D2 × H)^1.006; these two coefficients are not consistent with exp(-3.571) = 0.02813 (0.028953 is close to exp(-3.571) × 1.029, and 0.029821 looks like the correction applied twice). This record uses the printed log-log equation with the printed CF 1.029 (coefficient 0.02894); the paper's 0.029821 form gives about 3% more biomass. Sample was 98 trees for model development (n_trees) plus 22 for validation (120 in total), per the Sampling section, p. 204.
doi:10.26525/jtfs2021.33.2.203 · Open access · copy we read
7 -3.571 1.006 ... 1.029
In the first event, 98 individuals were chosen to derive the allometric model, covering diameter at breast height and total height range of 9–52 cm and 9–37 m respectively.
diameter at breast height (9–52 cm) and total height (9–37 m)
- Trees measured
- 98
- DBH range
- 9–52 cm
- Height range
- 9–37 m
- R²
- 0.96
- Residual SE
- 0.243
- Correction factor
- 1.029 (applied)
- Method
- log-log regression (natural log) with Sprugel correction factor; semi-destructive
- Where
- Rema-Kalenga Wildlife Sanctuary, Sylhet region, Bangladesh
- 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 = 15, H = 15 | 102.6 | 102.6 | Computed from the printed form computed from the published form (exp of the printed log-log equation times the printed CF 1.029) |
| D = 30, H = 22 | 608.1 | 608.1 | Computed from the printed form computed from the published form (exp of the printed log-log equation times the printed CF 1.029) |
| D = 45, H = 30 | 1,878 | 1,878 | Computed from the printed form computed from the published form (exp of the printed log-log equation times the printed CF 1.029) |
Related
- C. tabularis height from D (1/H = a + b/D, Model 3) · same paper · Height