# Radiata pine needle from DBH (Eq. 8)

Foliage biomass equation for Pinus radiata, South Africa, from Pienaar et al. 2025. DBH 10.4–38.9 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Pienaar et al. 2025 (Table 3):

> Needle, Eq. 8, Ln(DBH): β0 = -2.481, β1 = 1.624, CF = 1.057

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#equation

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

```
Foliage biomass = 1.057 * exp(-2.481 + 1.624*ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 1.057 * exp(-2.481 + 1.624*ln(DBH)), with DBH in cm, H in m; output in kg.
Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#canonical

## What it covers

- Output: Foliage biomass, kg
- Taxon: Pinus radiata (species), family Pinaceae; conifer
- Where: Boland region, Western Cape, South Africa. Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#where
- Biomes: temperate
- Stand: plantation
- DBH range: 10.4–38.9 cm. Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#dbh
- R²: 0.69. Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#r2
- Correction factor: 1.057 (applied). Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#cf
- Method: ln-ln linear regression (R lm), Baskerville correction factor. Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#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

Pienaar, L. O., Calama, R., Olivar, J., et al. (2025). Allometric equations for biomass and carbon pool estimation in short rotation Pinus radiata stands of the Western Cape, South Africa. European Journal of Forest Research, 144, 855–873.

- DOI: https://doi.org/10.1007/s10342-024-01730-9
- Access: open access
- Copy we read: https://link.springer.com/article/10.1007/s10342-024-01730-9
- Every equation from this source: https://treeallometry.org/sources/pienaar-2025/
- Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#source

## The facts, in the source's words

**Equation** (Table 3):

> Needle, Eq. 8, Ln(DBH): β0 = -2.481, β1 = 1.624, CF = 1.057

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#equation

**Equation** (Table 3 footnote):

> ln (Y) = β0 + β1ln(X1) + ⋯ + βjln(Χj) needs to be multiplied by the CF to transform the values to the arithmetic scale

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#quote-expression

**R²** (Table 3):

> R2 = 0.69

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#quote-fit-r2

**Smallest DBH** (Discussion):

> the sample trees in this study range from 10.4 cm to 38.9 cm

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#quote-fit-dbh-min-cm

**Our note:** Natural-log model; correction factor CF = exp(RSE²/2) (Baskerville) as printed in Table 3 is applied in the expression. H is total tree height (m). Stand-level site: 4 plantation sites aged 13 to 20 years. Needle and branch tree-level totals come from branch-level upscaling; two outliers were removed, leaving 18 trees, so n is not entered here. Biomass is oven-dry mass. Eq. 10 is the authors' best model for stemwood and total.

## 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 = 14 | 7.19 | 7.19 | Computed from the printed form: computed from the published form |
| D = 30, H = 22 | 22.2 | 22.2 | Computed from the printed form: computed from the published form |

Cite: https://treeallometry.org/equations/pienaar-2025-foliage-eq8/#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: Pienaar, L. O., Calama, R., Olivar, J., et al. (2025). Allometric equations for biomass and carbon pool estimation in short rotation Pinus radiata stands of the Western Cape, South Africa. European Journal of Forest Research, 144, 855–873. https://doi.org/10.1007/s10342-024-01730-9

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Radiata pine needle from DBH (Eq. 8)", checked 2026-11-02, https://treeallometry.org/equations/pienaar-2025-foliage-eq8/. 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/pienaar-2025-foliage-eq8.json
Report a problem: email info@restorationscope.com with the equation id (pienaar-2025-foliage-eq8) and where the right value appears.