# Peat swamp forest, all species, volume from D (model 3)

Stem volume equation for Mixed peat swamp forest species (6 species, Dipterocarpaceae and others), Indonesia, from Qirom & Akbar 2020. 84 trees, DBH 5.6–29.2 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Qirom & Akbar 2020 (Best model, all species, p. 10 (Tabel 3 model 3)):

> V = 0.00042 D2.22540 dengan R2 95,5 %

Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#equation

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

```
Stem volume = 0.00042 * D^2.2254
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 0.00042 * DBH^2.2254, with DBH in cm; output in m3.
Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#canonical

## What it covers

- Output: Stem volume, m³
- Taxon: Mixed peat swamp forest species (6 species, Dipterocarpaceae and others) (mixed species); broadleaf
- Where: IUPHHK PT Tingang Karya Mandiri peat swamp forest, Central Kalimantan. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 84. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#n_trees
- DBH range: 5.6–29.2 cm. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#dbh
- Height range: 6–24 m. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#height
- R²: 0.955. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#r2
- Method: ordinary least squares, non-linear power form V = a0 D^a1. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#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

Qirom, M. A., & Akbar, A. (2020). Model Volume Kelompok Jenis Pohon pada Hutan Rawa Gambut di IUPHHK PT. Tingang Karya Mandiri, Kalimantan Tengah [The Volume Model of Tree Species Group in Peat Swamp Forest at Logging Concession Area of Tingang Karya Mandiri, Central Kalimantan]. Jurnal WASIAN, 7(1), 1-14.

- DOI: https://doi.org/10.20886/jwas.v7i1.5538
- Access: open access
- Copy we read: https://pub.kehutanan.unismuh.ac.id/index.php/wasian/article/download/97/88
- Every equation from this source: https://treeallometry.org/sources/qirom-2020/
- Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#source

## The facts, in the source's words

**Equation** (Best model, all species, p. 10 (Tabel 3 model 3)):

> V = 0.00042 D2.22540 dengan R2 95,5 %

Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#equation

**Trees measured** (Tabel 1, Penyusunan Model):

> Keseluruhan jenis Diameter 13,4 5,6 29,2 5,3 84

Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#quote-fit-n-trees

**Our note:** Volume to a 5 cm top diameter by Smalian's formula on 2 m sections (stem volume, no branches). Diameter was taken at 1.3 m or 20 cm above ground (as printed: 'setinggi dada (1,3 m) atau 20 cm di atas permukaan tanah'); the paper does not say which trees used which. Natural-log form as printed, with no correction factor stated. Fit ranges are those of the model-development subset (70% of the trees, Table 1).

## 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 | 0.043 | 0.043 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 15 | 0.174 | 0.174 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 25 | 0.542 | 0.542 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/qirom-2020-all-species-d/#checks

## How to cite

Cite the source for the equation: Qirom, M. A., & Akbar, A. (2020). Model Volume Kelompok Jenis Pohon pada Hutan Rawa Gambut di IUPHHK PT. Tingang Karya Mandiri, Kalimantan Tengah [The Volume Model of Tree Species Group in Peat Swamp Forest at Logging Concession Area of Tingang Karya Mandiri, Central Kalimantan]. Jurnal WASIAN, 7(1), 1-14. https://doi.org/10.20886/jwas.v7i1.5538

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Peat swamp forest, all species, volume from D (model 3)", checked 2026-11-02, https://treeallometry.org/equations/qirom-2020-all-species-d/. 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/qirom-2020-all-species-d.json
Report a problem: email info@restorationscope.com with the equation id (qirom-2020-all-species-d) and where the right value appears.