# Rubber (PR107) stem volume from D and H (Eq. 9, Schumacher-Hall)

Stem volume equation for Hevea brasiliensis (clone PR107), Cambodia, from Khun et al. 2008. 60 trees, DBH 20–62 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Khun et al. 2008 (Eqs. 8-9, p. 338):

> log V = -3.73563 + 2.23961 log D + 0.15334 log H (R2 = 0.9245, N = 60), or V = 0.00018381 D^2.23961 H^0.15334

Cite: https://treeallometry.org/equations/khun-2008-v-dh/#equation

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

```
Stem volume = 0.00018381 * D^2.23961 * H^0.15334
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 0.00018381 * D^2.23961 * H^0.15334, with D in cm, H in m; output in m3.
Cite: https://treeallometry.org/equations/khun-2008-v-dh/#canonical

## What it covers

- Output: Stem volume, m³
- Taxon: Hevea brasiliensis (clone PR107) (species), family Euphorbiaceae; broadleaf
- Where: Krek Rubber Plantation, Kompong Cham Province. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#where
- Biomes: tropical
- Stand: plantation
- Trees measured: 60. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#n_trees
- DBH range: 20–62 cm. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#dbh
- Height range: 16.7–47 m. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#height
- R²: 0.9245. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#r2
- Method: log-log linear regression (log10) of over-bark stem volume on D (and H), 60 felled trees, ages 36-46 years. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/khun-2008-v-dh/#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

Khun, K., Mizoue, N., Yoshida, S., & Murakami, T. (2008). Stem Volume Equation and Tree Growth For Rubber Trees in Cambodia. Journal of Forest Planning, 13, 335-341.

- DOI: https://doi.org/10.20659/jfp.13.2_335
- Access: open access
- Copy we read: https://www.jstage.jst.go.jp/article/jfp/13/2/13_KJ00007911384/_pdf
- Every equation from this source: https://treeallometry.org/sources/khun-2008/
- Cite: https://treeallometry.org/equations/khun-2008-v-dh/#source

## The facts, in the source's words

**Equation** (Eqs. 8-9, p. 338):

> log V = -3.73563 + 2.23961 log D + 0.15334 log H (R2 = 0.9245, N = 60), or V = 0.00018381 D^2.23961 H^0.15334

Cite: https://treeallometry.org/equations/khun-2008-v-dh/#equation

**R²** (Eq. 8, p. 338):

> R2 = 0.9245, N = 60

Cite: https://treeallometry.org/equations/khun-2008-v-dh/#quote-fit-r2

**Smallest DBH** (Results and Discussion, Volume Equations, p. 338):

> The range of data is 20-62cm for DBH, 16.7-47.0m for total height, and 0.25 to 3.41m³ for stem volume.

Cite: https://treeallometry.org/equations/khun-2008-v-dh/#quote-fit-dbh-min-cm

**Our note:** Volume is over-bark stem volume of 60 felled PR107 trees (1 m sections, Smalian). Logs are base 10: 10^-3.6041 = 0.00024884 and 10^-3.73563 = 0.00018381 as printed. R2 is of the log-log regression. Ranges follow the text on p. 338; Table 1 (p. 337) prints per-stand minima/maxima whose overall span is DBH 26.0-62.0 cm and height 16.2-47.3 m, which does not match the text exactly.

## 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 = 28 | 0.623 | 0.623 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 45, H = 32 | 1.58 | 1.58 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/khun-2008-v-dh/#checks

## How to cite

Cite the source for the equation: Khun, K., Mizoue, N., Yoshida, S., & Murakami, T. (2008). Stem Volume Equation and Tree Growth For Rubber Trees in Cambodia. Journal of Forest Planning, 13, 335-341. https://doi.org/10.20659/jfp.13.2_335

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Rubber (PR107) stem volume from D and H (Eq. 9, Schumacher-Hall)", checked 2026-11-02, https://treeallometry.org/equations/khun-2008-v-dh/. 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/khun-2008-v-dh.json
Report a problem: email info@restorationscope.com with the equation id (khun-2008-v-dh) and where the right value appears.