Tree Allometrics

Acacia mearnsii / Stem biomass

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

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

As printed (Table 3, Stem biomass model 1)

Stem biomass 1. a + b(DH)c 0.99 0.01 1.75 98.64

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

Stem biomass = 0.99 + 0.01 * (D * H)^1.75
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
0.9864
Method
nonlinear regression, form a + b(DH)^c
Where
Farmer-managed woodlots, northwestern Ethiopia (Amhara)
Last checked
2026-11-02
Calculate
Height from
1.33
Stem biomass (kg)
0.625
Carbon (kg), ×0.47
2.29
CO₂e (kg), ×44/12
Fitted DBH range05101520253035510152025303540DBH (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 = 3, H = 2.51.331.33Computed from the printed form
computed from the published form
D = 7, H = 4.45.025.02Computed from the printed form
computed from the published form
D = 11, H = 6.518.618.6Computed from the printed form
computed from the published form

Report a problem with this equation · JSON

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