Tree Allometrics

Equations / Aboveground biomass

Acacia mearnsii Aboveground biomass from D and H (Table 3, model 1)

Aboveground biomassAcacia mearnsii · FabaceaeEthiopiaplantationRead from the original paper
Photo of Acacia mearnsii
© Chris Ecroyd · CC BY · iNaturalist
Equation

As printed (Table 3, AGB model 1; Conclusion)

1.92 + 0.02(DH)1.68

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

Aboveground biomass = 1.92 + 0.02 * (D * H)^1.68
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Coefficients are printed to two decimals only, so predictions are coarse for small trees. D is DBH in cm, H in m, biomass in kg (Table 2). Trees aged 3 to 6 years. R2 printed as a percentage and converted to a fraction. Table 3 was read from the journal CSV download; the column order is a, b, c, R2, RMSE, MAD, AIC, p. Stem, AGB and total biomass model 1 are the best models per the authors. Branch and leaf models are not added (Table 3: R2 about 0.5 for branches and about 0.6 for leaves).

Source
twenty-four trees of varying ages (3, 4, 5, and 6 years) were harvested
Trees measured · Abstract
Tree parameters DBH (cm) 24 1.1 7.1 11.9; Height (m) 24 2.1 4.4 6.8 (n, min, mean, max)
Smallest DBH · Table 2
Trees measured
24
DBH range
1.1–11.9 cm
Height range
2.1–6.8 m
R²
0.9749
Method
nonlinear regression, form a + b(DH)^c
Where
Farmer-managed woodlots, northwestern Ethiopia (Amhara)
Last checked
2026-11-02
Calculate
Height from
2.51
Aboveground biomass (kg)
1.18
Carbon (kg), ×0.47
4.326
CO₂e (kg), ×44/12
Fitted DBH range01020304050510152025303540DBH (cm)Aboveground biomass (kg)Aboveground 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 = 3, H = 2.52.512.51Computed from the printed form
computed from the published form
D = 7, H = 4.48.268.26Computed from the printed form
computed from the published form
D = 11, H = 6.52828Computed from the printed form
computed from the published form

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