# NZ shrubland shrubs and small trees, dry weight from basal area x height

Aboveground biomass equation for Shrubland shrubs and small trees, all species (Kunzea ericoides, Leptospermum scoparium, Ulex europaeus, Cytisus scoparius and others), New Zealand, from Mason et al. 2014. 162 trees. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

Fitted on Kunzea ericoides, Leptospermum scoparium, Ulex europaeus, Cytisus scoparius, and other species the source does not name here.

## Equation

As printed in Mason et al. 2014 (Eq. 1 and Figure 3 caption):

> Dry weight = exp(a • ln(basal area • height) + b) ... fitted on the entire harvested shrub dataset with a = 1.0215 and b = 6.1512

Cite: https://treeallometry.org/equations/mason-2014-agb/#equation

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

```
Aboveground biomass = exp(1.0215 * ln(0.785398163397448 * (DRC / 100)^2 * H) + 6.1512)
```

Inputs: DRC = Root collar / stem base diameter (cm); H = Total tree height (m).
The source's own form: exp(1.0215 * ln(0.785398163397448 * (DRC / 100)^2 * H) + 6.1512), with DRC in cm, H in m; output in kg.
Cite: https://treeallometry.org/equations/mason-2014-agb/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Shrubland shrubs and small trees, all species (Kunzea ericoides, Leptospermum scoparium, Ulex europaeus, Cytisus scoparius and others) (mixed species); shrub
- Where: Oxford (Canterbury) and d'Urville Island, South Island, New Zealand. Cite: https://treeallometry.org/equations/mason-2014-agb/#where
- Biomes: temperate
- Stand: natural
- Trees measured: 162. Cite: https://treeallometry.org/equations/mason-2014-agb/#n_trees
- R²: 0.93. Cite: https://treeallometry.org/equations/mason-2014-agb/#r2
- Method: iterative function minimisation of residual sum of squares, DW = exp(a ln(BA x Height) + b). Cite: https://treeallometry.org/equations/mason-2014-agb/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/mason-2014-agb/#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

Mason, N. W. H., Beets, P. N., Payton, I., Burrows, L., Holdaway, R. J., & Carswell, F. E. (2014). Individual-Based Allometric Equations Accurately Measure Carbon Storage and Sequestration in Shrublands. Forests, 5(2), 309–324.

- DOI: https://doi.org/10.3390/f5020309
- Access: open access
- Copy we read: https://www.mdpi.com/1999-4907/5/2/309/htm
- Every equation from this source: https://treeallometry.org/sources/mason-2014/
- Cite: https://treeallometry.org/equations/mason-2014-agb/#source

## The facts, in the source's words

**Equation** (Eq. 1 and Figure 3 caption):

> Dry weight = exp(a • ln(basal area • height) + b) ... fitted on the entire harvested shrub dataset with a = 1.0215 and b = 6.1512

Cite: https://treeallometry.org/equations/mason-2014-agb/#equation

**Trees measured** (Section 2.3):

> Overall, 162 shrubs were harvested.

Cite: https://treeallometry.org/equations/mason-2014-agb/#quote-fit-n-trees

**R²** (Section 3):

> The basal area × height allometric equation accurately (R-square = 0.93) predicted shrub dry weight

Cite: https://treeallometry.org/equations/mason-2014-agb/#quote-fit-r2

**Our note:** Paper predictor is total shrub basal area BA (m2, summed over all stems of the shrub) times maximum shrub height (m). BA is written here as pi/4 * (DRC/100)^2 so DRC is the basal diameter of a single stem, or the equivalent diameter sqrt(sum of d^2) for a multi-stemmed shrub. No back-transform correction is stated. Dry weight is of the whole harvested shrub (foliage and stem were weighed separately and, as the text reads, combined).

## 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 |
| --- | --- | --- | --- |
| DRC = 3, H = 2 | 0.576 | 0.576 | Computed from the printed form: computed from the published form (coefficients as printed) |
| DRC = 8, H = 4 | 8.68 | 8.68 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/mason-2014-agb/#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: Mason, N. W. H., Beets, P. N., Payton, I., Burrows, L., Holdaway, R. J., & Carswell, F. E. (2014). Individual-Based Allometric Equations Accurately Measure Carbon Storage and Sequestration in Shrublands. Forests, 5(2), 309–324. https://doi.org/10.3390/f5020309

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "NZ shrubland shrubs and small trees, dry weight from basal area x height", checked 2026-11-02, https://treeallometry.org/equations/mason-2014-agb/. 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/mason-2014-agb.json
Report a problem: email info@restorationscope.com with the equation id (mason-2014-agb) and where the right value appears.