# Alnus acuminata (aliso) AGB, sum of SUR component models (DBH, height)

Aboveground biomass equation for Alnus acuminata, Ecuador, from Riofrío et al. 2013. 30 trees, DBH 9.3–20.3 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, Aliso, Fuste):

> W f = 0,1483*DBH2+0,003688*DBH2*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#equation

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

```
Aboveground biomass = 0.347148 * D^2 + 0.003688 * D^2 * H - 1.267285 * H
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 0.1483*DBH^2 + 0.003688*DBH^2*Ht + 0.080183*DBH^2 - 0.569041*Ht + 0.085229*DBH^2 - 0.483528*Ht + 0.033436*DBH^2 - 0.214716*Ht, with DBH in cm, Ht in m; output in kg.
Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Alnus acuminata (species), family Betulaceae; 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-alnus-acuminata/#where
- Biomes: tropical, montane
- Stand: agroforestry
- Trees measured: 30. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#n_trees
- DBH range: 9.3–20.3 cm. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#dbh
- Height range: 6.8–12.8 m. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#height
- R²: 0.938. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#r2
- Method: Component models (stem, coarse branches, thin branches, leaves) fitted simultaneously by seemingly unrelated regression (SUR); total = sum of components. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#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-alnus-acuminata/#source

## The facts, in the source's words

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

> W f = 0,1483*DBH2+0,003688*DBH2*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#equation

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

> W rg = 0,080183*DBH2 - 0,569041*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#quote-expression

**Equation** (Tabla 4, Aliso, Ramillas delgadas):

> W rd = 0,085229DBH2 - 0,483528*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#quote-expression-2

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

> W h = 0,033436*DBH2 - 0,214716*Ht

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#quote-expression-3

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

> Biomasa total 9,72 0,938

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#quote-fit-r2

**Smallest DBH** (Tabla 1 (n, DBH mean SD min max, Ht mean SD min max)):

> Aliso 30 14,5 3,2 9,3 20,3 10,7 1,4 6,8 12,8

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

**Our note:** Total aboveground dry biomass (kg) is the sum of the four additive SUR component equations in Tabla 4 (stem with bark, coarse branches 2–7 cm, thin branches <2 cm, leaves); the paper prints no single total equation. r2 is the adjusted R² of total biomass. Linear models, no log correction. The negative height terms make predictions unreliable for short, thick trees outside the fitted range. A journal version is Riofrío et al. (2015) Biomass and Bioenergy 80:252-259 (not read).

## 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 = 14.5, H = 10.7 | 67.7 | 67.7 | Computed from the printed form: computed from the sum of published components at the sample means (observed mean Wt 71,1 kg, Tabla 1) |
| D = 20, H = 12 | 141.4 | 141.4 | Computed from the printed form: computed from the sum of published components |

Cite: https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/#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), "Alnus acuminata (aliso) AGB, sum of SUR component models (DBH, height)", checked 2026-11-01, https://treeallometry.org/equations/riofrio-2013-alnus-acuminata/. 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-alnus-acuminata.json
Report a problem: email info@restorationscope.com with the equation id (riofrio-2013-alnus-acuminata) and where the right value appears.