Equations / Aboveground biomass
US national species group: Spruce (Table 4)
As printed (Table 4 footnote, p. 20)
In this library's units, ready to compute (kg)
Aboveground biomass = exp(-2.0773 + 2.3323 * ln(D))D- Diameter at breast height (1.3 m), cm
Group membership: Picea (Table 3). dbh_max_cm is the 'Max dbh of trees measured in published equations'; data points are pseudodata, not trees. Hardwood groups were extended to 230 cm dbh with Freedman (1984) pseudodata. No log-bias correction: the authors deliberately omit it; a user could multiply by exp(RMSE²/2) = 1.0319. Superseded for FIA reporting by NSVB (Westfall et al. 2024) but still widely used in carbon protocols.
doi:10.1093/forestscience/49.1.12 · Open access · copy we read
Spruce −2.0773 2.3323 212 250 0.250424 0.988
bm = total aboveground biomass (kg) for trees 2.5cm dbh and larger
Root mean squared error or estimate of the standard deviation of the regression error term in natural log units.
we do not include CFs for the reader to use after back-transformation
- DBH range
- 2.5–250 cm
- R²
- 0.988
- Residual SE
- 0.250424
- Method
- OLS on ln-transformed pseudodata (212 points, generally at 5 cm dbh intervals) generated from published equations; no back-transform correction applied
- Where
- Conterminous United States
- Last checked
- 2026-11-01
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 = 30 | 349.1 | 349.1 | Computed from the printed form computed from the published form at dbh = 30 cm |
| D = 10 | 26.9 | 26.9 | Computed from the printed form computed from the published form at dbh = 10 cm |
Related
- US national species group: Aspen/alder/cottonwood/willow (Table 4) · same paper · Aboveground biomass
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