# Total AGB from DBH, power law (Eq. 12)

Aboveground biomass equation for Seven dominant canopy species (Carapa guianensis, Inga coruscans, Laetia procera, Pentaclethra macroloba, Stryphnodendron microstachyum, Tapirira guianensis, Vochysia ferruginea), Costa Rica, from Segura & Kanninen 2005. 19 trees, DBH 60–105 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

Fitted on Carapa guianensis, Inga coruscans, Laetia procera, Pentaclethra macroloba, Stryphnodendron microstachyum, Tapirira guianensis, Vochysia ferruginea.

## Equation

As printed in Segura & Kanninen 2005 (Table 5, Eq. 12):

> ln B tot = c + a ln DBH; c −7.27 ± 1.37; a 2.07 ± 0.31

Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#equation

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

```
Aboveground biomass = 1000 * exp(-7.27 + 2.07 * ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-7.27 + 2.07 * ln(DBH)), with DBH in cm; output in Mg.
Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Seven dominant canopy species (Carapa guianensis, Inga coruscans, Laetia procera, Pentaclethra macroloba, Stryphnodendron microstachyum, Tapirira guianensis, Vochysia ferruginea) (mixed species); broadleaf
- Where: Tirimbina (Sarapiquí) and Corinto (Guápiles), northern Costa Rica. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 19. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#n_trees
- DBH range: 60–105 cm. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#dbh
- R²: 0.71. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#r2
- Method: Least-squares regression (SAS), r2 is the adjusted coefficient of determination. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#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

Segura, M., & Kanninen, M. (2005). Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica. Biotropica, 37(1), 2–8.

- DOI: https://doi.org/10.1111/j.1744-7429.2005.02027.x
- Access: open access
- Copy we read: https://www.cifor-icraf.org/publications/pdf_files/articles/ASegura0501.pdf
- Every equation from this source: https://treeallometry.org/sources/segura-2005/
- Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#source

## The facts, in the source's words

**Equation** (Table 5, Eq. 12):

> ln B tot = c + a ln DBH; c −7.27 ± 1.37; a 2.07 ± 0.31

Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#equation

**Trees measured** (Methods, p. 3):

> 19 individual trees were measured before harvest

Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#quote-fit-n-trees

**Largest DBH** (Discussion, p. 7):

> adjusted well in the interval of diameters sampled (60–105 cm)

Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#quote-fit-dbh-max-cm

**Our note:** No back-transform correction factor is stated, so none is applied. Only trees with DBH ≥ 60 cm were harvested; the authors warn the models tend to overestimate outside 60-105 cm. Table 5 gives B tot in 'mg/tree', meaning Mg (Table 3 reports total biomass in Mg, mean 6.7 Mg); the canonical expression multiplies by 1000 to give kg. Recommended by the authors because it needs DBH only.

## 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 = 80 | 6,054 | 6,054 | Computed from the printed form: computed from the printed coefficients |

Cite: https://treeallometry.org/equations/segura-2005-btot-eq12/#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: Segura, M., & Kanninen, M. (2005). Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica. Biotropica, 37(1), 2–8. https://doi.org/10.1111/j.1744-7429.2005.02027.x

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Total AGB from DBH, power law (Eq. 12)", checked 2026-11-02, https://treeallometry.org/equations/segura-2005-btot-eq12/. 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/segura-2005-btot-eq12.json
Report a problem: email info@restorationscope.com with the equation id (segura-2005-btot-eq12) and where the right value appears.