# Commercial stem volume from DBH, Mezilaurus itauba (species-specific, Table 2)

Stem volume equation for Mezilaurus itauba, Brazil, from Santos et al. 2020. 593 trees, DBH from 50 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Santos et al. 2020 (Table 2, SSEs rows):

> M. itauba vc = exp(-7.25817 + 2.05543ln(DBH)) 0.68 1.712 26.2

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#equation

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

```
Stem volume = exp(-7.25817 + 2.05543 * ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-7.25817 + 2.05543 * ln(DBH)), with DBH in cm; output in m3.
Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#canonical

## What it covers

- Output: Stem volume, m³
- Taxon: Mezilaurus itauba (species), family Lauraceae; broadleaf
- Where: Tapajós National Forest, Pará (community forest management concession), eastern Brazilian Amazon. Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 593. Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#n_trees
- DBH range: from 50 cm. Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#dbh
- R²: 0.68. Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#r2
- Method: Model 2 (Husch) fitted by least squares on ln(vc); r2 is the adjusted R² recalculated in arithmetic units; Syx = 1.712 m3 (26.2%). Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#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

Santos, M.F. dos, Figueiredo Filho, A., Gama, J.R.V., Retslaff, F.A. de S., Costa, D.L. da (2020). Species-specific equations: greater precision in commercial volume estimation in managed forests in the Amazon. CERNE, 26(3), 315-330.

- DOI: https://doi.org/10.1590/01047760202026032741
- Access: open access
- Copy we read: https://www.scielo.br/j/cerne/a/wVP9VN9KTRZwBYfg8yngfPL/?lang=en&format=pdf
- Every equation from this source: https://treeallometry.org/sources/santos-2020/
- Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#source

## The facts, in the source's words

**Equation** (Table 2, SSEs rows):

> M. itauba vc = exp(-7.25817 + 2.05543ln(DBH)) 0.68 1.712 26.2

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#equation

**Trees measured** (Table 1 (columns: adjustment, validation)):

> Mezilaurus itauba (Meisn.) Taub. ex Mez. Itaúba 593 65

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#quote-fit-n-trees

**Smallest DBH** (Material and Methods, Data collection):

> 29,119 trees (50.0 cm ≤ DBH ≤ 175.0 cm) of 43 commercial species

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#quote-fit-dbh-min-cm

**Output** (Material and Methods, Data collection):

> composed the commercial volume (vc) of the stem

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#quote-output

**Our note:** Species-specific equation (M. itauba, Itaúba). vc is the commercial volume of the stem (sum of Smalian log volumes, hollows discounted), not total tree volume. No back-transformation correction factor is stated, so none is applied. n_trees is the adjustment (fitting) set; DBH range is that of the whole dataset (all species), not stated per species. Ten percent of trees were held out for validation. 8 of the 36+1 species equations in Table 2 were added (the ten most important commercial species by harvested volume plus H. petraeum); the generic FMA equation was rejected by the authors' own paired t-test. 

## 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 = 60 | 3.18 | 3.18 | Computed from the printed form: hand-computed from the Table 2 coefficients |
| D = 90 | 7.32 | 7.32 | Computed from the printed form: hand-computed from the Table 2 coefficients |
| D = 130 | 15.6 | 15.6 | Computed from the printed form: hand-computed from the Table 2 coefficients |

Cite: https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/#checks

## How to cite

Cite the source for the equation: Santos, M.F. dos, Figueiredo Filho, A., Gama, J.R.V., Retslaff, F.A. de S., Costa, D.L. da (2020). Species-specific equations: greater precision in commercial volume estimation in managed forests in the Amazon. CERNE, 26(3), 315-330. https://doi.org/10.1590/01047760202026032741

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Commercial stem volume from DBH, Mezilaurus itauba (species-specific, Table 2)", checked 2026-11-02, https://treeallometry.org/equations/santos-2020-mezilaurus-itauba/. 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/santos-2020-mezilaurus-itauba.json
Report a problem: email info@restorationscope.com with the equation id (santos-2020-mezilaurus-itauba) and where the right value appears.