# Acacia melanoxylon AGB in Andean agroforestry, sum of SUR component models (DBH, height)

Aboveground biomass equation for Acacia melanoxylon, Ecuador, from Riofrío et al. 2013. 30 trees, DBH 13.4–31.5 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Riofrío et al. 2013 (Tabla 4, Acacia, Fuste):

> W f = 0,083622*DBH 1,826783 *Ht 0,689611

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#equation

In this library's units, ready to compute (aboveground biomass in kg):

```
Aboveground biomass = 0.083622 * D^1.826783 * H^0.689611 + 0.365815 * D^2 - 1.044164 * H - 0.170251 * D * H
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 0.083622*DBH^1.826783*Ht^0.689611 + 0.101503*DBH^2 - 1.044164*Ht + 0.144577*DBH^2 - 0.094715*DBH*Ht + 0.119735*DBH^2 - 0.075536*DBH*Ht, with DBH in cm, Ht in m; output in kg.
Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Acacia melanoxylon (species), family Fabaceae; broadleaf
- Where: Two INIAP agroforestry systems, inter-Andean western cordillera of northern/central Ecuador, above 3000 m (Bosque Siempreverde Montano Alto). Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#where
- Biomes: tropical, montane
- Stand: agroforestry
- Trees measured: 30. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#n_trees
- DBH range: 13.4–31.5 cm. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#dbh
- Height range: 11.3–24.3 m. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#height
- R²: 0.906. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#r2
- Method: Component models (stem, coarse branches, thin branches, leaves) fitted by SUR; total = sum of components. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#checked_at

A missing fit statistic is one the source doesn't state, or that we haven't recorded; it is never estimated. Outside the stated DBH range or region, the equation is an extrapolation.

## Source

Riofrío, J., Herrero de Aza, C., Grijalva, J., & Bravo, F. (2013). Modelos para estimar la biomasa de especies forestales en sistemas agroforestales de la ecorregión andina del Ecuador. 6º Congreso Forestal Español, Vitoria-Gasteiz, Spain. Paper 6CFE01-023.

- Link: https://www.congresoforestal.es/actas/doc/6CFE/6CFE01-023.pdf
- Access: open access
- Every equation from this source: https://treeallometry.org/sources/riofrio-2013/
- Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#source

## The facts, in the source's words

**Equation** (Tabla 4, Acacia, Fuste):

> W f = 0,083622*DBH 1,826783 *Ht 0,689611

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#equation

**Equation** (Tabla 4, Acacia, Ramas gruesas):

> W rg = 0,101503*DBH2 – 1,044164*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#quote-expression

**Equation** (Tabla 4, Acacia, Ramas delgadas):

> W rd = 0,144577*DBH2 - 0,094715*DBH*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#quote-expression-2

**Equation** (Tabla 4, Acacia, Hojas):

> W h = 0,119735*DBH2 - 0,075536*DBH*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#quote-expression-3

**R²** (Tabla 4, Acacia (RMSE kg, R2 ajustado)):

> Biomasa total 44,34 0,906

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#quote-fit-r2

**Smallest DBH** (Tabla 1):

> Acacia 30 22,4 4,4 13,4 31,5 17,9 2,4 11,3 24,3

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#quote-fit-dbh-min-cm

**Our note:** Introduced species widely planted in Andean agroforestry. Total aboveground dry biomass (kg) is the sum of the four Tabla 4 component equations; exponents printed as superscripts in the stem model.

## Checks this equation passes

On every build, the library's form and the source's own form (in its units) must both give these values within 1%.

| Inputs | Expected | We get | From |
| --- | --- | --- | --- |
| D = 22.4, H = 17.9 | 276 | 276 | Computed from the printed form: computed at the sample means (observed mean Wt 286,8 kg, Tabla 1) |

Cite: https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/#checks

The calculator on the page shows carbon as biomass × 0.47 (IPCC 2006 Guidelines, Vol. 4, Ch. 4, Table 4.3) and CO₂e as carbon × 44/12.

## How to cite

Cite the source for the equation: Riofrío, J., Herrero de Aza, C., Grijalva, J., & Bravo, F. (2013). Modelos para estimar la biomasa de especies forestales en sistemas agroforestales de la ecorregión andina del Ecuador. 6º Congreso Forestal Español, Vitoria-Gasteiz, Spain. Paper 6CFE01-023.

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Acacia melanoxylon AGB in Andean agroforestry, sum of SUR component models (DBH, height)", checked 2026-11-01, https://treeallometry.org/equations/riofrio-2013-acacia-melanoxylon/. Data CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Quotes are the authors' words.

Data for this equation: https://treeallometry.org/data/equations/riofrio-2013-acacia-melanoxylon.json
Report a problem: email info@restorationscope.com with the equation id (riofrio-2013-acacia-melanoxylon) and where the right value appears.