# Teak stem volume from D (V1, local)

Stem volume equation for Tectona grandis, Nepal, from Koirala et al. 2017. 31 trees, DBH 6.37–58.92 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Koirala et al. 2017 (Table 6 (form V1), Table 7 (estimates)):

> V = a + b × (dbh) ... a -0.4720, b 0.0414

Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#equation

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

```
Stem volume = -0.4720 + 0.0414 * D
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: -0.4720 + 0.0414 * dbh, with dbh in cm; output in m3.
Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#canonical

## What it covers

- Output: Stem volume, m³
- Taxon: Tectona grandis (species), family Lamiaceae; broadleaf
- Where: Sagarnath Forestry Development Project, Sarlahi district, central lowland Nepal. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#where
- Biomes: tropical
- Stand: plantation
- Trees measured: 31. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#n_trees
- DBH range: 6.37–58.92 cm. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#dbh
- Height range: 5.7–26.1 m. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#height
- R²: 0.949. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#r2
- Method: least squares on training set (31 of 44 felled trees). Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#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

Koirala, A., Kizha, A. R., & Baral, S. (2017). Modeling height-diameter relationship and volume of teak (Tectona grandis L.f.) in central lowlands of Nepal. Journal of Tropical Forestry and Environment, 7(1), 28–42.

- DOI: https://doi.org/10.31357/jtfe.v7i1.3020
- Access: open access
- Copy we read: https://web.archive.org/web/2024/http://journals.sjp.ac.lk/index.php/JTFE/article/download/3020/2093
- Every equation from this source: https://treeallometry.org/sources/koirala-2017/
- Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#source

## The facts, in the source's words

**Equation** (Table 6 (form V1), Table 7 (estimates)):

> V = a + b × (dbh) ... a -0.4720, b 0.0414

Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#equation

**Trees measured** (Section 2.2):

> 31 (70 % of the data) were randomly selected to build the model

Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#quote-fit-n-trees

**Our note:** Volume is the total stem volume above the 0.10 m stump (stump excluded), summed from log sections and the tree top. Paper calls V1 the local volume equation. R2 0.949 (adj. 0.944), RMSE 0.20 m3 (Table 7). Predicts negative volume for small trees.

## 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 | 0.356 | 0.356 | Computed from the printed form: computed from the published form (coefficients as printed); not meaningful below about 11.4 cm (negative volume) |
| D = 35 | 0.977 | 0.977 | Computed from the printed form: computed from the published form (coefficients as printed); not meaningful below about 11.4 cm (negative volume) |
| D = 55 | 1.81 | 1.81 | Computed from the printed form: computed from the published form (coefficients as printed); not meaningful below about 11.4 cm (negative volume) |

Cite: https://treeallometry.org/equations/koirala-2017-v-dbh/#checks

## How to cite

Cite the source for the equation: Koirala, A., Kizha, A. R., & Baral, S. (2017). Modeling height-diameter relationship and volume of teak (Tectona grandis L.f.) in central lowlands of Nepal. Journal of Tropical Forestry and Environment, 7(1), 28–42. https://doi.org/10.31357/jtfe.v7i1.3020

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Teak stem volume from D (V1, local)", checked 2026-11-02, https://treeallometry.org/equations/koirala-2017-v-dbh/. 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/koirala-2017-v-dbh.json
Report a problem: email info@restorationscope.com with the equation id (koirala-2017-v-dbh) and where the right value appears.