Tree Allometrics

Equations / Stem biomass

Quercus suber stem with bark biomass (Table 2)

Stem biomassQuercus suber · FagaceaeSpainmixedRead from the original paper
Photo of Quercus suber
© Duarte Frade · CC BY · iNaturalist
Equation

As printed (Table 2, Quercus suber, Stem row)

Ws = 0.00525 · d² · h + 0.278 · d · h

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

Stem biomass = 0.00525 * D^2 * H + 0.278 * D * H
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Stem with bark (commercial volume, up to a top diameter of 7 cm); fitted jointly with the branch equations by SUR to keep components additive. Stand type is not stated per species in the paper. Branch equations for this species are not added.

Source
Quercus suber ... 33
Trees measured · Table 1, Quercus suber row, aboveground biomass n column
Quercus suber 10.5 83.0
Smallest DBH · Table 1, diameter min/max (all sample trees of the species)
Trees measured
33
DBH range
10.5–83 cm
Height range
3.5–14 m
Method
seemingly unrelated regression with weighting
Where
Spain (sample zones per species, Figure 1)
Last checked
2026-11-02
Calculate
Height from
76.6
Stem biomass (kg)
36
Carbon (kg), ×0.47
132
CO₂e (kg), ×44/12
Fitted DBH range050100150200510152025303540DBH (cm)Stem biomass (kg)Stem 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 = 20, H = 1076.676.6Computed from the printed form
computed from the Table 2 coefficients
D = 35, H = 15242.4242.4Computed from the printed form
computed from the Table 2 coefficients

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