# Shorea assamica height from D, Power model (best fit, Table 4)

Height equation for Shorea assamica, Indonesia, from Wirabuana et al. 2025. 1,009 trees, DBH 20–67 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Wirabuana et al. 2025 (Table 1 and Table 4, Power row):

> Power H = a.DBH^b; a = 2.11, b = 0.55

Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#equation

In this library's units, ready to compute (height in m):

```
Height = 2.11 * D^0.55
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 2.11 * DBH^0.55, with DBH in cm; output in m.
Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#canonical

## What it covers

- Output: Height, m
- Taxon: Shorea assamica (species), family Dipterocarpaceae; broadleaf
- Where: Tabalong District, South Kalimantan (PT Aya Yayang Indonesia concession, secondary lowland dipterocarp forest). Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 1,009. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#n_trees
- DBH range: 20–67 cm. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#dbh
- Height range: 11–28 m. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#height
- R²: 0.74. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#r2
- Method: nonlinear least squares height-diameter model, fitted on 1009 of 1440 trees. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#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

Wirabuana, P., Nugroho, Y., & Mulyana, B. (2025). Diameter-Height relationship model for Shorea assamica in secondary tropical rainforest, South Borneo. Journal of Sylva Indonesiana, 8(2), 82-91.

- DOI: https://doi.org/10.32734/jsi.v8i2.18749
- Access: open access
- Copy we read: https://talenta.usu.ac.id/Jsi/article/download/18749/9304
- Every equation from this source: https://treeallometry.org/sources/wirabuana-2025/
- Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#source

## The facts, in the source's words

**Equation** (Table 1 and Table 4, Power row):

> Power H = a.DBH^b; a = 2.11, b = 0.55

Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#equation

**Trees measured** (Section 3.1):

> 1009 tree height and diameter datasets were utilized

Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#quote-fit-n-trees

**R²** (Table 4):

> R2 0.74

Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#quote-fit-r2

**Our note:** Selected by the authors as the best-fit model. Fitted on the 70% model-development subset (1009 trees); DBH and height ranges are that subset (Table 3). Only trees with DBH >= 20 cm were recorded. Coefficients are printed to two decimals. The paper also lists Exponential and Gompertz models (Table 4) that were not added: the Exponential b is printed as 0.01 (too coarse to reproduce the fit) and the Gompertz coefficients as printed (a=152.37, b=0.01, c=170.49) do not give a sensible curve.

## 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 = 25 | 12.4 | 12.4 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 40 | 16 | 16 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 60 | 20.1 | 20.1 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/wirabuana-2025-h-power/#checks

## How to cite

Cite the source for the equation: Wirabuana, P., Nugroho, Y., & Mulyana, B. (2025). Diameter-Height relationship model for Shorea assamica in secondary tropical rainforest, South Borneo. Journal of Sylva Indonesiana, 8(2), 82-91. https://doi.org/10.32734/jsi.v8i2.18749

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Shorea assamica height from D, Power model (best fit, Table 4)", checked 2026-11-02, https://treeallometry.org/equations/wirabuana-2025-h-power/. 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/wirabuana-2025-h-power.json
Report a problem: email info@restorationscope.com with the equation id (wirabuana-2025-h-power) and where the right value appears.