# North American taxa group: Cupressaceae 0.30–0.39 spg (Table 5)

Aboveground biomass equation for Cupressaceae 0.30–0.39 spg (Calocedrus decurrens, Sequoiadendron giganteum, Thuja plicata), United States, from Chojnacky et al. 2014. DBH 3–614 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

Fitted on Calocedrus decurrens, Sequoiadendron giganteum, Thuja plicata.

## 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-cupressaceae-spg-030-039/#equation

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

```
Aboveground biomass = exp(-2.7765 + 2.4195 * ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-2.7765 + 2.4195 * ln(dbh)), with dbh in cm; output in kg.
Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Cupressaceae 0.30–0.39 spg (Calocedrus decurrens, Sequoiadendron giganteum, Thuja plicata) (mixed species), family Cupressaceae; conifer
- Where: United States (equations compiled from US and Canadian studies). Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#where
- Biomes: temperate
- Stand: mixed
- DBH range: 3–614 cm. Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#dbh
- R²: 0.76. Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#r2
- Method: Weighted regression of ln(biomass) on ln(dbh) fitted to 164 pseudodata points generated from 10 published equations; no back-transform correction. Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#method
- Verification: read in the original source
- Last checked: 2026-11-03. Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#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-cupressaceae-spg-030-039/#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-cupressaceae-spg-030-039/#equation

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

> Cupressaceae 0.30–0.39 spg 0.34 −2.7765 2.4195 164 10 dbh 3–614 0.76

Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#quote-expression

**Taxon** (Table 2, p. 135):

> Sequoiadendron giganteum Sequoia, giant 212 0.34 1

Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#quote-taxon

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

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

Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#quote-fit-cf

**Our note:** Incense-cedar, giant sequoia and western redcedar. The 614 cm upper diameter comes from the giant sequoia equation. Median specific gravity of the group: 0.34. 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 | 233 | 233 | Computed from the printed form: computed from the published form at dbh = 30 cm |

Cite: https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/#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: Cupressaceae 0.30–0.39 spg (Table 5)", checked 2026-11-03, https://treeallometry.org/equations/chojnacky-2014-cupressaceae-spg-030-039/. 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-cupressaceae-spg-030-039.json
Report a problem: email info@restorationscope.com with the equation id (chojnacky-2014-cupressaceae-spg-030-039) and where the right value appears.