Androstachys johnsonii / Root biomass
Root system dry biomass from DBH and height (Table 4, form 5)
As printed (Table 4, Root system rows, and Eq. (5; Ŷ = b0 × DBH^b1 × TH^b2))
In this library's units, ready to compute (kg)
Root biomass = 0.0185 * D^2.199 * H^0.4699D- Diameter at breast height (1.3 m), cm
H- Total tree height, m
Ranked below the D²H form (form 6) by CVr but the author notes height improved fit only negligibly and prefers DBH-only or RCD-only models. Weight function 1/(0.000008 × DBH^1.7645). Root system = taproot (including root collar) + lateral roots, excavated to full depth, fine roots included, dry mass at 105 C; stump above 20 cm is not part of it. Independent (not WNSUR additive) model, which the author recommends over the simultaneous ones. One of four independent root-system models in Table 4; all performed almost equally.
doi:10.1186/s13021-015-0027-4 · Open access · copy we read
93 trees (DBH range 5–32 cm; TH range 5.69–16 m)
DBH range 5–32 cm
Root system 2 99.78 23.4060
The dry weight of the root system was obtained by summing the dry weights of taproot and lateral roots (fine and coarse ones).
- Trees measured
- 93
- DBH range
- 5–32 cm
- Height range
- 5.69–16 m
- R²
- 0.9978
- Method
- Weighted nonlinear least squares (nls, Gauss-Newton); r2 is the adjusted R² in Table 5; CVr = 23.406%
- Where
- Mabote, Funhalouro, Panda, Mandlakaze and Chibuto districts, Inhambane and Gaza provinces
- 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 = 8, H = 7 | 4.47 | 4.47 | Computed from the printed form hand-computed from the Table 4 coefficients |
| D = 15, H = 10 | 21.1 | 21.1 | Computed from the printed form hand-computed from the Table 4 coefficients |
| D = 25, H = 13 | 73.2 | 73.2 | Computed from the printed form hand-computed from the Table 4 coefficients |
Related
- Root system dry biomass from DBH²·H (Table 4, form 6) · Magalhães 2015 · DBH + Height
- Root system dry biomass from DBH (Table 4, form 4) · Magalhães 2015 · DBH
- Root system dry biomass from root collar diameter (Table 4, form 7) · Magalhães 2015 · Root collar diameter
- Root system dry biomass from DBH²·H (Table 4, form 6) · same paper · Root biomass
- Root system dry biomass from DBH (Table 4, form 4) · same paper · Root biomass
- Root system dry biomass from root collar diameter (Table 4, form 7) · same paper · Root biomass