Equations / Root biomass
BGB Model 6 (DBH and [ln(DBH)]²), peat swamp forest Sarawak
As printed (Models section, p. 15)
In this library's units, ready to compute (kg)
Root biomass = 1.1267 * exp(-6.1049 + 3.9957 * ln(D) - 0.2322 * ln(D)^2)D- Diameter at breast height (1.3 m), cm
Coefficients a-e as printed in Table 5; the e term enters with a minus sign per the model definitions. WD is wood density in Mg m-3, numerically equal to g/cm3. Back-transformed result multiplied by the printed CF. Adjusted R2 0.9544 is not entered as r2. DW is dry mass (kg) of the whole above- or belowground part; hollow cavity volume was measured separately and the models are fitted to the measured biomass of hollow trees.
doi:10.3759/tropics.24.11 · Open access · copy we read
Model 6 −6.1049 3.9957 *** 0.2322 ns 0.9544 1.1267 49.81 0.02378
Belowground biomass (n＝32)
BGB data for trees ranging in DBH from 5.2 to 110.8 cm
- Trees measured
- 32
- DBH range
- 5.2–110.8 cm
- Correction factor
- 1.1267 (applied)
- Method
- log-log regression of dry weight on ln-transformed predictors, back-transformed and multiplied by the correction factor CF = exp(RSE²/2)
- Where
- Logged-over peat swamp forest, Sarawak (Alan Batu and other sites, PC1-PC3)
- 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 = 10 | 7.27 | 7.27 | Computed from the printed form computed from the published form (coefficients and CF as printed) |
| D = 30 | 136.8 | 136.8 | Computed from the printed form computed from the published form (coefficients and CF as printed) |
| D = 60 | 653 | 653 | Computed from the printed form computed from the published form (coefficients and CF as printed) |
Related
- BGB Model 1 (DBH, H, WD), peat swamp forest Sarawak · Monda et al. 2015 · DBH + Height + Wood density
- BGB Model 5 (DBH only), peat swamp forest Sarawak · Monda et al. 2015 · DBH
- AGB Model 1 (DBH, H, WD), peat swamp forest Sarawak · same paper · Aboveground biomass
- AGB Model 2 (DBH, H, WD and [ln(DBH)]²), peat swamp forest Sarawak · same paper · Aboveground biomass
- AGB Model 3 (DBH, H and [ln(DBH)]²), peat swamp forest Sarawak · same paper · Aboveground biomass
- AGB Model 4 (DBH, WD and [ln(DBH)]²), peat swamp forest Sarawak · same paper · Aboveground biomass
- AGB Model 5 (DBH only), peat swamp forest Sarawak · same paper · Aboveground biomass
- AGB Model 6 (DBH and [ln(DBH)]²), peat swamp forest Sarawak · same paper · Aboveground biomass
- BGB Model 1 (DBH, H, WD), peat swamp forest Sarawak · same paper · Root biomass
- BGB Model 5 (DBH only), peat swamp forest Sarawak · same paper · Root biomass