# Piscidia piscipula, additive system S2 (D²H, Eq. 7-10): branch biomass

Branch biomass equation for Piscidia piscipula (L.) Sarg., Mexico, from Cuevas Cruz et al. 2022. 17 trees, DBH 5.7–55 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Cuevas Cruz et al. 2022 (Eq. 8, Table 2 (S2)):

> Br = e^[−β20+β21 ln(Dn² AT)] + ε2 (8); Table 2, S2 Ramas: β20 4.00219, β21 0.950832

Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#equation

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

```
Branch biomass = exp(-4.00219 + 0.950832 * ln(D^2 * H))
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: exp(-4.00219 + 0.950832 * ln(Dn^2 * AT)), with AT in m, Dn in cm; output in kg.
Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#canonical

## What it covers

- Output: Branch biomass, kg
- Taxon: Piscidia piscipula (L.) Sarg. (species), family Fabaceae; broadleaf
- Where: Escárcega, Campeche (selva mediana subperennifolia). Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 17. Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#n_trees
- DBH range: 5.7–55 cm. Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#dbh
- Height range: 8.12–21 m. Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#height
- Method: Additive nonlinear system of component equations fitted simultaneously by generalized method of moments (GMM). Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#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

Cuevas Cruz, J. C., Aquino Ramírez, M., Kú Chalé, R. de la C., & Morales Sosa, I. J. (2022). Ecuaciones alométricas aditivas para estimar biomasa aérea y concentración de carbono de Piscidia piscipula (L.) Sarg. Madera y Bosques, 28(3), e2832356.

- DOI: https://doi.org/10.21829/myb.2022.2832356
- Access: open access
- Copy we read: https://myb.ojs.inecol.mx/index.php/myb/article/download/2356/2424
- Every equation from this source: https://treeallometry.org/sources/cuevas-2022/
- Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#source

## The facts, in the source's words

**Equation** (Eq. 8, Table 2 (S2)):

> Br = e^[−β20+β21 ln(Dn² AT)] + ε2 (8); Table 2, S2 Ramas: β20 4.00219, β21 0.950832

Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#equation

**Trees measured** (Resumen / Table 1):

> destructivo de 17 individuos

Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#quote-fit-n-trees

**Our note:** The paper prints the intercept as a positive estimate and the model with a minus sign in front of it (e^[−β0 + ...]); applied that way. Adjusted R2 (not stored): stem 0.9821, branches 0.9769, twigs with leaves 0.8419, total 0.9931 (Table 3). Dn and AT are the paper's diameter at breast height and total height.

## 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 = 20.5, H = 12 | 60.6 | 60.6 | Computed from the printed form: computed from the published form (Table 2 coefficients, intercept with the printed minus sign) |
| D = 40.2, H = 17.1 | 305 | 305 | Computed from the printed form: computed from the published form (Table 2 coefficients, intercept with the printed minus sign) |

Cite: https://treeallometry.org/equations/cuevas-2022-s2-branch/#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: Cuevas Cruz, J. C., Aquino Ramírez, M., Kú Chalé, R. de la C., & Morales Sosa, I. J. (2022). Ecuaciones alométricas aditivas para estimar biomasa aérea y concentración de carbono de Piscidia piscipula (L.) Sarg. Madera y Bosques, 28(3), e2832356. https://doi.org/10.21829/myb.2022.2832356

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Piscidia piscipula, additive system S2 (D²H, Eq. 7-10): branch biomass", checked 2026-11-02, https://treeallometry.org/equations/cuevas-2022-s2-branch/. 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/cuevas-2022-s2-branch.json
Report a problem: email info@restorationscope.com with the equation id (cuevas-2022-s2-branch) and where the right value appears.