# Shorea assamica height from D, Linear model (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, Linear row):

> Linear H = a + b.DBH; a = 6.97, b = 0.23

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

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

```
Height = 6.97 + 0.23 * D
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 6.97 + 0.23 * DBH, with DBH in cm; output in m.
Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#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-linear/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 1,009. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#n_trees
- DBH range: 20–67 cm. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#dbh
- Height range: 11–28 m. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#height
- R²: 0.72. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#r2
- Method: nonlinear least squares height-diameter model, fitted on 1009 of 1440 trees. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#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-linear/#source

## The facts, in the source's words

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

> Linear H = a + b.DBH; a = 6.97, b = 0.23

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

**Trees measured** (Section 3.1):

> 1009 tree height and diameter datasets were utilized

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

**R²** (Table 4):

> R2 0.72

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

**Our note:** 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 | 12.7 | 12.7 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 40 | 16.2 | 16.2 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 60 | 20.8 | 20.8 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/wirabuana-2025-h-linear/#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, Linear model (Table 4)", checked 2026-11-02, https://treeallometry.org/equations/wirabuana-2025-h-linear/. 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-linear.json
Report a problem: email info@restorationscope.com with the equation id (wirabuana-2025-h-linear) and where the right value appears.