# North American taxa group: Oleaceae < 0.55 spg (Table 5)

Aboveground biomass equation for Oleaceae < 0.55 spg (Fraxinus nigra, F. pennsylvanica, Fraxinus spp.), United States, from Chojnacky et al. 2014. DBH 3–43 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

Fitted on Fraxinus nigra, Fraxinus pennsylvanica, and other species the source does not name here.

## Equation

As printed in Chojnacky et al. 2014 (Table 5 caption, p. 140):

> ln(biomass) = β0 + β1 ln(diameter)

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#equation

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

```
Aboveground biomass = exp(-2.0314 + 2.3524 * ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-2.0314 + 2.3524 * ln(dbh)), with dbh in cm; output in kg.
Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Oleaceae < 0.55 spg (Fraxinus nigra, F. pennsylvanica, Fraxinus spp.) (mixed species), family Oleaceae; broadleaf
- Where: United States (equations compiled from US and Canadian studies). Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#where
- Biomes: temperate
- Stand: mixed
- DBH range: 3–43 cm. Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#dbh
- R²: 0.84. Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#r2
- Method: Weighted regression of ln(biomass) on ln(dbh) fitted to 54 pseudodata points generated from 9 published equations; no back-transform correction. Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#method
- Verification: read in the original source
- Last checked: 2026-11-03. Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#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

Chojnacky, D.C., Heath, L.S., Jenkins, J.C. (2014). Updated generalized biomass equations for North American tree species. Forestry, 87(1), 129–151.

- DOI: https://doi.org/10.1093/forestry/cpt053
- Access: open access
- Copy we read: https://research.fs.usda.gov/download/treesearch/45402.pdf
- Every equation from this source: https://treeallometry.org/sources/chojnacky-2014/
- Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#source

## The facts, in the source's words

**Equation** (Table 5 caption, p. 140):

> ln(biomass) = β0 + β1 ln(diameter)

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#equation

**Equation** (Table 5 row, p. 140):

> Oleaceae < 0.55 spg 0.51 −2.0314 2.3524 54 9 dbh 3–43 0.84

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#quote-expression

**Taxon** (Table 3, p. 137):

> Oleaceae Fraxinus nigra Ash, black 543 0.45 4

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#quote-taxon

**Correction factor** (Methods, p. 139):

> we did not include a correction (Baskerville, 1972) for underestimation

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#quote-fit-cf

**Our note:** Black and green ash, plus 'Fraxinus spp.'. Median specific gravity of the group: 0.51. Diameter range is that of the pseudodata. R² is the published 'R²-statistic'.

## 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 = 30 | 391 | 391 | Computed from the printed form: computed from the published form at dbh = 30 cm |

Cite: https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/#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: Chojnacky, D.C., Heath, L.S., Jenkins, J.C. (2014). Updated generalized biomass equations for North American tree species. Forestry, 87(1), 129–151. https://doi.org/10.1093/forestry/cpt053

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "North American taxa group: Oleaceae < 0.55 spg (Table 5)", checked 2026-11-03, https://treeallometry.org/equations/chojnacky-2014-oleaceae-spg-lt-055/. 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/chojnacky-2014-oleaceae-spg-lt-055.json
Report a problem: email info@restorationscope.com with the equation id (chojnacky-2014-oleaceae-spg-lt-055) and where the right value appears.