Tree Allometrics

Vachellia tortilis / Aboveground biomass

Vachellia tortilis total aboveground biomass (Model 4)

Aboveground biomassVachellia tortilisEthiopiaRead from the original paperPeer-reviewed sourceNot fully checked

Not fully checked: Section 2.3.3 says M4 requires only stump diameter, whereas Tables 1, 5 and 6 and Fig. 4 include total height. This record uses the explicitly parameterized equation in Table 5; confirm the conflicting description with the authors before relying on it.

Photo of Vachellia tortilis
© Rabah Al-Shammary · CC BY · iNaturalist
Equation

As printed (Fig. 4 caption, full equation for M₄, p. 11; corresponding fit in Table 5, Total Model 4 row, p. 9)

Y = 0.31dₛₕ^1.731 h^0.633

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

Aboveground biomass = 0.31 * D30^1.731 * H^0.633
D30
Stem diameter at 30 cm, cm
H
Total tree height, m

Nonlinear power regression on the original scale; no back-transformation or correction is stated or applied. dsh is diameter at 30 cm above ground and h is total height. For multi-stemmed trees use the square root of the sum of squared stem diameters at the relevant height (Eq. 1). The harvested stump-diameter range was 3.2–44.5 cm. The authors recommend M4 for precise carbon accounting.

Source
Model 4 Y = β1dshβ2h β3 0.31 1.731*** 0.633** 0.97 36.55 0.605 29.558 0.90 1
Equation · Table 5, Total Model 4, p. 9
Total
Output · Table 5, biomass component, p. 9
biomass (kg dry matter/
Units · Table 5 heading, p. 9
ith stem at stump or breast height (cm).
Units · Eq. 1 definition, p. 4
d: diameter at breast height (1.30 m); dsh:stump diameter at 30 cm height; h: total
Units · Table 5 note, p. 9
height of plant (m)
Units · Table 5 note, p. 9
kg per plant, n: 15
Trees measured · Table 5 note, p. 9
Model 4 Y = β1dshβ2h β3 0.31 1.731*** 0.633** 0.97 36.55 0.605 29.558 0.90 1
R² · Table 5, Total Model 4, p. 9
non-linear power function
method · Abstract, p. 1
Vachellia tortilis
Taxon · Study area, p. 3
Adami Tullu Jido Kombolcha district
Where · Study area, p. 2
semi-arid climate zone
Where · Study area, p. 2
Trees measured
15
R²
0.97
Method
nonlinear power regression
Where
Adami Tullu Jido Kombolcha district, Central Rift Valley, Ethiopia
Last checked
2026-11-05
Calculate
Height from
111
Aboveground biomass (kg)
52.2
Carbon (kg), ×0.47
191
CO₂e (kg), ×44/12
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
D30 = 20, H = 3111111Computed from the printed form
Computed from the printed Table 5 coefficients; no individual published prediction with all inputs is provided.

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