Tree Allometrics

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Birch total root biomass, disaggregated model (Eq. 24), Heilongjiang site

Root biomassBetula platyphylla · BetulaceaeChinaplantationRead from the original paper
Photo of Betula platyphylla
© harum.koh · CC BY-SA · iNaturalist
Equation

As printed (Eq. 24, Section 3.3)

ft(D, H; βt) = exp[Bt1 + βt2 ln DBH + βt3 ln HT + βts2S2 + βts3S3]

In this library's units, ready to compute (kg)

Root biomass = exp(-1.0113 + 2.2706 * ln(D) - 0.8676 * ln(H))
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Total root biomass function ft of the disaggregated system. Site: Heilongjiang (Maoer mountains), baseline site with S2 = 0 and S3 = 0. The paper fits one model with site dummies (Liaoning when S2 = 1 and S3 = 0, Jilin when S2 = 0 and S3 = 1, Heilongjiang when S2 = 0 and S3 = 0); this file sets the dummies for one site. It is fitted on all 493 trees from the three sites (Heilongjiang 333, Jilin 26, Liaoning 134 per Table 1), so the site term is a shift on common slopes. The paper reports no back-transform correction factor for the log-normal error and none is applied. The paper reports only ten-fold cross-validation R2, not a fit R2, so none is given here. Roots were excavated and sieved into coarse (>5 mm), medium (2-5 mm) and fine (<2 mm) classes; the total includes all three.

Source
with a total of 493 sample trees
Trees measured · Section 2.1
Min 3.40 4.50 0.10 0.02 0.02 0.14
Smallest DBH · Table 2 (DBH 3.4 cm, HT 4.5 m minimum)
Max 11.90 14.00 9.29 10.19 3.98 20.27
Largest DBH · Table 2 (DBH 11.9 cm, HT 14.0 m maximum)
ft βt1 −1.0113 0.1807 0.0000; βt2 2.2706 0.1251 0.0000; βt3 −0.8676 0.12 0.0000; βts2 −0.0108 0.0946 0.9088; βts3 −0.6541 0.0682 0.0000
Equation · Table 6
Trees measured
493
DBH range
3.4–11.9 cm
Height range
4.5–14 m
Method
log-transformed (multiplicative error) nonlinear system with site dummies
Where
Maoer mountains, Heilongjiang Province, Northeast China
Last checked
2026-11-02
Calculate
Height from
5.849
Root biomass (kg)
2.749
Carbon (kg), ×0.47
10.08
CO₂e (kg), ×44/12
Fitted DBH range050100150200250510152025303540DBH (cm)Root biomass (kg)Root biomass

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%.

InputsExpectedWe getFrom
D = 8, H = 9.45.855.85Computed from the printed form
hand-computed from the published form
D = 11, H = 139.19.1Computed from the printed form
hand-computed from the published form

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