# Brachystegia spiciformis stem merchantable volume from D2H

Stem volume equation for Brachystegia spiciformis, Mozambique, from Manjate et al. 2025. 37 trees, DBH 17–81 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Manjate et al. 2025 (Table 4, stem merchantable wood volume under bark, Model 2):

> Y = 3.32 × 10−5 × (DBH2 × Ht)0.953

Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#equation

In this library's units, ready to compute (stem volume in m³):

```
Stem volume = 3.32e-05 * (D^2 * H)^0.953
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 3.32e-05 * (DBH^2 * Ht)^0.953, with DBH in cm, Ht in m; output in m3.
Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#canonical

## What it covers

- Output: Stem volume, m³
- Taxon: Brachystegia spiciformis (species), family Fabaceae; broadleaf
- Where: Levasflor forests, Cheringoma district, Sofala province. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#where
- Biomes: tropical, dryland
- Stand: natural
- Trees measured: 37. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#n_trees
- DBH range: 17–81 cm. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#dbh
- Height range: 12–26 m. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#height
- Method: Non-linear weighted power model, Y = b0 (DBH^2 Ht)^b1 x error. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#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

Manjate, A., Goodman, R., Zahabu, E., Ilstedt, U., & Egas, A. (2025). Allometric Models to Estimate the Merchantable Wood Volume and Biomass of the Most Abundant Miombo Species in the Miombo Woodlands in Mozambique. Earth, 6(2), 52.

- DOI: https://doi.org/10.3390/earth6020052
- Access: open access
- Copy we read: https://www.mdpi.com/2673-4834/6/2/52/htm
- Every equation from this source: https://treeallometry.org/sources/manjate-2025/
- Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#source

## The facts, in the source's words

**Equation** (Table 4, stem merchantable wood volume under bark, Model 2):

> Y = 3.32 × 10−5 × (DBH2 × Ht)0.953

Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#equation

**Trees measured** (Section 2.2):

> 37 B. spiciformis trees (DBH ranging from 17 to 81cm and height ranging from 12 to 26 m)

Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#quote-fit-n-trees

**Our note:** Model 2 (DBH2 x Ht) was the best of the three models by AIC and BIC. Volume is merchantable wood under bark (stem or branches down to a 15 cm top diameter over bark), in m3. No correction factor is stated. Stem part only (from 15 cm diameter over bark).

## 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 = 30, H = 15 | 0.287 | 0.287 | Computed from the printed form: computed from the published form |
| D = 50, H = 20 | 0.998 | 0.998 | Computed from the printed form: computed from the published form |

Cite: https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/#checks

## How to cite

Cite the source for the equation: Manjate, A., Goodman, R., Zahabu, E., Ilstedt, U., & Egas, A. (2025). Allometric Models to Estimate the Merchantable Wood Volume and Biomass of the Most Abundant Miombo Species in the Miombo Woodlands in Mozambique. Earth, 6(2), 52. https://doi.org/10.3390/earth6020052

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Brachystegia spiciformis stem merchantable volume from D2H", checked 2026-11-02, https://treeallometry.org/equations/manjate-2025-bspiciformis-stem-volume/. 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/manjate-2025-bspiciformis-stem-volume.json
Report a problem: email info@restorationscope.com with the equation id (manjate-2025-bspiciformis-stem-volume) and where the right value appears.