# Spotted gum AGB from D, H and wood density (Eq. 8)

Aboveground biomass equation for Corymbia citriodora subsp. variegata, Australia, from Huynh et al. 2022. 52 trees, DBH 11.8–42 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Huynh et al. 2022 (Table 4, Eq. (8); form in Table 2):

> (8) 0.00233 2.42585 0.30576 0.49890 for AGB = α × Dβ × Hβ1 × ρβ2

Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#equation

In this library's units, ready to compute (aboveground biomass in kg):

```
Aboveground biomass = 0.00233 * D^2.42585 * H^0.30576 * (rho * 1000)^0.4989
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m); rho = Wood density (oven-dry mass / green volume) (g/cm³).
The source's own form: 0.00233 * D^2.42585 * H^0.30576 * rho^0.4989, with D in cm, H in m, rho in kg/m3; output in kg.
Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Corymbia citriodora subsp. variegata (species), family Myrtaceae; broadleaf
- Where: Three plantation trials (451D, 451G, 13PHY), southeast Queensland. Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#where
- Biomes: subtropical
- Stand: plantation
- Trees measured: 52. Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#n_trees
- DBH range: 11.8–42 cm. Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#dbh
- Height range: 12.6–32 m. Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#height
- Method: weighted nonlinear regression (nlme). Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#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

Huynh, T., Lewis, T., Applegate, G., Pachas, A. N. A., & Lee, D. J. (2022). Allometric Equations to Estimate Aboveground Biomass in Spotted Gum (Corymbia citriodora Subspecies variegata) Plantations in Queensland. Forests, 13(3), 486.

- DOI: https://doi.org/10.3390/f13030486
- Access: open access
- Copy we read: https://www.mdpi.com/1999-4907/13/3/486/htm
- Every equation from this source: https://treeallometry.org/sources/huynh-2022/
- Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#source

## The facts, in the source's words

**Equation** (Table 4, Eq. (8); form in Table 2):

> (8) 0.00233 2.42585 0.30576 0.49890 for AGB = α × Dβ × Hβ1 × ρβ2

Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#equation

**Trees measured** (Abstract):

> We destructively sampled and weighed 52 sample trees, ranging from 11.8 to 42.0 cm in diameter at breast height

Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#quote-fit-n-trees

**Our note:** Weighted nonlinear power model, so no back-transform correction applies. AGB is the total of stem, bark, large branches, small branches and leaves (Table 3), so foliage is included. Adjusted R² is printed in Table 4 but is not stored. Wood density ρ is in kg m-3 in the paper, converted to g/cm3 in the canonical form.

## 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 = 15, H = 16, rho = 0.7 | 102 | 102 | Computed from the printed form: computed from the Table 4 parameter estimates |
| D = 30, H = 27, rho = 0.73 | 656 | 656 | Computed from the printed form: computed from the Table 4 parameter estimates |

Cite: https://treeallometry.org/equations/huynh-2022-eq8-dhrho/#checks

The calculator on the page shows carbon as biomass × 0.47 (IPCC 2006 Guidelines, Vol. 4, Ch. 4, Table 4.3) and CO₂e as carbon × 44/12.

## How to cite

Cite the source for the equation: Huynh, T., Lewis, T., Applegate, G., Pachas, A. N. A., & Lee, D. J. (2022). Allometric Equations to Estimate Aboveground Biomass in Spotted Gum (Corymbia citriodora Subspecies variegata) Plantations in Queensland. Forests, 13(3), 486. https://doi.org/10.3390/f13030486

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Spotted gum AGB from D, H and wood density (Eq. 8)", checked 2026-11-02, https://treeallometry.org/equations/huynh-2022-eq8-dhrho/. 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/huynh-2022-eq8-dhrho.json
Report a problem: email info@restorationscope.com with the equation id (huynh-2022-eq8-dhrho) and where the right value appears.