# Pinus halepensis stem biomass from DBH and height (combined variable)

Stem biomass equation for Pinus halepensis Mill., Mexico, from Marroquín Morales et al. 2018. 50 trees, DBH 6.9–22.8 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Marroquín Morales et al. 2018 (Cuadro 4 (Bf, modelo 2); R2 ajustada 0.85 in Cuadro 5):

> Bf  2  -1.198  0.30  0.633  0.04

Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#equation

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

```
Stem biomass = exp(-1.198 + 0.633*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(-1.198 + 0.633*ln(Dn^2*H)), with Dn in cm, H in m; output in kg.
Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#canonical

## What it covers

- Output: Stem biomass, kg
- Taxon: Pinus halepensis Mill. (species), family Pinaceae; conifer
- Where: Cuauhtémoc and El Recreo ejidos, Saltillo, Coahuila. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#where
- Biomes: dryland, temperate
- Stand: plantation
- Trees measured: 50. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#n_trees
- DBH range: 6.9–22.8 cm. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#dbh
- Height range: 3.1–6.7 m. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#height
- R²: 0.85. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#r2
- Method: ln-ln least squares in R; no correction factor stated. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#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

Marroquín Morales, P., Méndez González, J., Jiménez Pérez, J., Aguirre Calderón, O. A., & Yerena Yamallel, J. I. (2018). Estimación de biomasa aérea en Pinus cembroides Zucc. y Pinus halepensis Mill. en Saltillo, Coahuila. Revista Mexicana de Ciencias Forestales, 9(47).

- DOI: https://doi.org/10.29298/rmcf.v9i47.172
- Access: open access
- Copy we read: https://www.redalyc.org/journal/634/63457163006/html/
- Every equation from this source: https://treeallometry.org/sources/marroquin-2018/
- Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#source

## The facts, in the source's words

**Equation** (Cuadro 4 (Bf, modelo 2); R2 ajustada 0.85 in Cuadro 5):

> Bf  2  -1.198  0.30  0.633  0.04

Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#equation

**model form** (Cuadro 1, modelo 2 (Variable combinada)):

> ln B = β0 + β1 ln(Dn2 H) + ε

Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#quote-model-form

**Trees measured** (Resumen):

> con una muestra de 50 árboles por especie

Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#quote-fit-n-trees

**Our note:** Bf model 2, selected for P. halepensis in Resultados (modelo 2 for Bhr, Bf and Bt). The Cuadro 4 row lists the intercept then the slope. Leaves-branches (Bhr) model 2 is not stored: it combines two components with no matching output quantity. Decimal point in the original. Plantation 22 years old. Biomass by the indirect Adelaide method (leaves-branches by reference branch, stem by Smalian volume times basic density), so the stem and total values are not weighed directly. Cuadro 5 R2 is the adjusted R2. The paper prints no correction factor for the ln back-transform, so none is applied. Ranges are from Cuadro 2 (n = 50).

## 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 = 8, H = 4 | 10.1 | 10.1 | Computed from the printed form: computed from the published form (coefficients as printed, no correction factor) |
| D = 14, H = 5 | 23.6 | 23.6 | Computed from the printed form: computed from the published form (coefficients as printed, no correction factor) |
| D = 21, H = 6 | 44.3 | 44.3 | Computed from the printed form: computed from the published form (coefficients as printed, no correction factor) |

Cite: https://treeallometry.org/equations/marroquin-2018-halepensis-stem/#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: Marroquín Morales, P., Méndez González, J., Jiménez Pérez, J., Aguirre Calderón, O. A., & Yerena Yamallel, J. I. (2018). Estimación de biomasa aérea en Pinus cembroides Zucc. y Pinus halepensis Mill. en Saltillo, Coahuila. Revista Mexicana de Ciencias Forestales, 9(47). https://doi.org/10.29298/rmcf.v9i47.172

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Pinus halepensis stem biomass from DBH and height (combined variable)", checked 2026-11-02, https://treeallometry.org/equations/marroquin-2018-halepensis-stem/. 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/marroquin-2018-halepensis-stem.json
Report a problem: email info@restorationscope.com with the equation id (marroquin-2018-halepensis-stem) and where the right value appears.