Equations / Stem biomass
Birch stem biomass, young dense stands, N Sweden (Table 5)
Stem biomassBetula · BetulaceaeSwedennaturalRead from the original paper
Covers the whole genus
Equation
As printed (Table 5, p. 12)
Stem, kg, birch: Intercept −4.879; dbh/(dbh + n) 8.037; h/(h + m) 22.614; ln(h) −4.003; n 2; m 12; var(uk) 0.001; var(eki) 0.016
In this library's units, ready to compute (kg)
Stem biomass = exp(-4.879 + (0.001 + 0.016) / 2 + 8.037 * D / (D + 2) + (22.614) * H / (H + 12) + (-4.003) * ln(H))D- Diameter at breast height (1.3 m), cm
H- Total tree height, m
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. Birch coefficients are for Betula pendula and B. pubescens pooled.
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
- 86
- DBH range
- 1–11 cm
- Height range
- 1.8–8.6 m
- Method
- linear mixed model of ln(biomass) with random stand effect; ln(y) = Intercept + b1 dbh/(dbh + n) + b2 h/(h + m) + b3 ln(h)
- Where
- Six young, dense, naturally regenerated stands in northern Sweden (63.26-65.69 N)
- Last checked
- 2026-11-02
Calculate
Height from
2.94
Stem biomass (kg)
1.38
Carbon (kg), ×0.47
5.07
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, H = 5 | 2.94 | 2.94 | Computed from the printed form hand-computed from the Table 5 coefficients with the (var(u) + var(e))/2 intercept correction |
| D = 10, H = 8 | 12.8 | 12.8 | Computed from the printed form hand-computed from the Table 5 coefficients with the (var(u) + var(e))/2 intercept correction |
Related
- White birch stem biomass from D only (MS-2) (Table 5) · Dong et al. 2018 · DBH
- White birch stem biomass from D and H (MS-3) (Table 6) · Dong et al. 2018 · DBH + Height
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- Betula papyrifera stem biomass, cross-sectional area at 0.3 m (NLS) · Flade et al. 2021 · D30
- Betula pendula stem in bark biomass vs DBH (Eq. 4), forest-swamp, Middle Urals · Petrova et al. 2026 · DBH
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