Tree Allometrics

Acacia mearnsii / Root biomass

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

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

As printed (Conclusion, and Figure 3 caption (BGB = 0.01D2.57 H0.09))

0.01D2.57H0.09

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

Root biomass = 0.01 * D^2.57 * H^0.09
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Coefficient a is printed as 0.01 (two decimals), so predictions are coarse. D in cm, H in m, biomass in kg. Trees aged 3 to 6 years. R2 printed as 92.41 percent. Root biomass sampled as total root dry weight (coarse, medium and fine roots).

Source
Below ground biomass 3. aDbHc 0.01 2.57 0.09 92.41
R² · Table 3 (CSV rows)
twenty-four trees of varying ages (3, 4, 5, and 6 years) were harvested
Trees measured · Abstract
Trees measured
24
DBH range
1.1–11.9 cm
Height range
2.1–6.8 m
R²
0.9241
Method
nonlinear regression, form a D^b H^c
Where
Farmer-managed woodlots, northwestern Ethiopia (Amhara)
Last checked
2026-11-02
Calculate
Height from
0.183
Root biomass (kg)
0.0859
Carbon (kg), ×0.47
0.315
CO₂e (kg), ×44/12
Fitted DBH range020406080100120140160510152025303540DBH (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 = 3, H = 2.50.1830.183Computed from the printed form
computed from the published form
D = 7, H = 4.41.71.7Computed from the printed form
computed from the published form
D = 11, H = 6.55.625.62Computed from the printed form
computed from the published form

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