Equations / Stem biomass
Norway spruce stem biomass, young dense stands, N Sweden (Table 5)
Stem biomassPicea abies · PinaceaeSwedennaturalRead from the original paper
© Douglas Goldman · CC BY-SA · iNaturalistEquation
As printed (Table 5, p. 12)
Stem, kg, Norway spruce: Intercept −2.669; dbh/(dbh + n) 10.482; n 10; var(uk) 0.010; var(eki) 0.020
In this library's units, ready to compute (kg)
Stem biomass = exp(-2.669 + (0.010 + 0.020) / 2 + 10.482 * D / (D + 10))D- Diameter at breast height (1.3 m), cm
Fitted on pine-dominated mixed stands; fit n, DBH and height ranges are the species sample ranges. Expression applies the paper's stated additive correction (var(uk) + var(eki))/2 to the intercept. Variance values are as printed in Table 5; no other correction factor is stated. Height is not an input for this model (low dbh-h variation).
Source
doi:10.14214/sf.1190 · Open access · copy we read
a variance correction term, ((var(uk) + var(eki))/2) should be added to the intercept to correct for bias due to the logarithmic transformation
In total, 280 trees were included in this destructive aboveground biomass study, of which 126 were pine, 68 spruce and 86 birch.
The range of dbh was 1–22 cm, 1–21 cm and 1–11 cm for pine, spruce and birch, respectively
The range of heights was 1.7–11.7 m, 1.6–13.3 m and 1.8–8.6 m for pine, spruce and birch, respectively
- Trees measured
- 68
- DBH range
- 1–21 cm
- Height range
- 1.6–13.3 m
- Method
- linear mixed model of ln(biomass) with random stand effect; ln(y) = Intercept + b1 dbh/(dbh + n)
- Where
- Six young, dense, naturally regenerated stands in northern Sweden (63.26-65.69 N)
- Last checked
- 2026-11-02
Calculate
2.316
Stem biomass (kg)
1.089
Carbon (kg), ×0.47
3.992
CO₂e (kg), ×44/12
Shaded: the DBH range the model was fitted on. Other inputs held at the values above.
Checks this equation passes
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 = 5 | 2.32 | 2.32 | Computed from the printed form hand-computed from the Table 5 coefficients with the (var(u) + var(e))/2 intercept correction |
| D = 12 | 21.4 | 21.4 | Computed from the printed form hand-computed from the Table 5 coefficients with the (var(u) + var(e))/2 intercept correction |
Related
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- Picea spp. stem biomass, cross-sectional area at 0.3 m (LLRC) · Flade et al. 2021 · D30
- Picea spp. stem biomass, cross-sectional area at 0.3 m (NLS) · Flade et al. 2021 · D30
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