# Pantropical AGB without height, with stress index E (Eq. 7)

Aboveground biomass equation for Tropical trees (58 sites), Pantropical, from Chave et al. 2014. 4,004 trees, DBH 5–212 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Chave et al. 2014 (Eq. 7, p. 3183):

> AGBest = exp[−1.803 − 0.976E + 0.976 ln(ρ) + 2.673 ln(D) − 0.0299[ln(D)]²]

Cite: https://treeallometry.org/equations/chave-2014-eq7/#equation

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

```
Aboveground biomass = exp(-1.803 - 0.976 * E + 0.976 * ln(rho) + 2.673 * ln(D) - 0.0299 * (ln(D))^2)
```

Inputs: E = Environmental stress index (Chave et al. 2014); rho = Wood density (oven-dry mass / green volume) (g/cm³); D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-1.803 - 0.976 * E + 0.976 * ln(rho) + 2.673 * ln(D) - 0.0299 * (ln(D))^2), with D in cm, rho in g/cm3, E in unitless; output in kg.
Cite: https://treeallometry.org/equations/chave-2014-eq7/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Tropical trees (58 sites) (mixed species); broadleaf
- Where: 58 harvest sites across the tropics. Cite: https://treeallometry.org/equations/chave-2014-eq7/#where
- Biomes: tropical, subtropical, dryland
- Stand: natural
- Trees measured: 4,004. Cite: https://treeallometry.org/equations/chave-2014-eq7/#n_trees
- DBH range: 5–212 cm. Cite: https://treeallometry.org/equations/chave-2014-eq7/#dbh
- Residual SE: 0.413. Cite: https://treeallometry.org/equations/chave-2014-eq7/#rse
- Method: log-scale regression on E, ln(ρ), ln(D), ln(D)². Cite: https://treeallometry.org/equations/chave-2014-eq7/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/chave-2014-eq7/#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

Chave, J., Réjou-Méchain, M., Búrquez, A., et al. (2014). Improved allometric models to estimate the aboveground biomass of tropical trees. Global Change Biology, 20(10), 3177–3190.

- DOI: https://doi.org/10.1111/gcb.12629
- Access: paywalled
- Copy we read: https://forestgeo.si.edu/sites/default/files/aboveground_biomass_protocol_accessible.pdf
- Every equation from this source: https://treeallometry.org/sources/chave-2014/
- Cite: https://treeallometry.org/equations/chave-2014-eq7/#source

## The facts, in the source's words

**Equation** (Eq. 7, p. 3183):

> AGBest = exp[−1.803 − 0.976E + 0.976 ln(ρ) + 2.673 ln(D) − 0.0299[ln(D)]²]

Cite: https://treeallometry.org/equations/chave-2014-eq7/#equation

**Residual standard error** (Eq. 7, p. 3183):

> (AIC = 4293, σ = 0.413, df = 3999)

Cite: https://treeallometry.org/equations/chave-2014-eq7/#quote-fit-rse

**Note** (Results, p. 3183):

> We therefore propose Model 7 for estimating AGB in the absence of height measurements.

Cite: https://treeallometry.org/equations/chave-2014-eq7/#quote-notes

**Units** (Results, p. 3182):

> where D is in cm, H is in m, and ρ is in g cm−3

Cite: https://treeallometry.org/equations/chave-2014-eq7/#quote-published-units

**Trees measured** (Abstract, p. 3177):

> 4004 trees ≥ 5 cm trunk diameter

Cite: https://treeallometry.org/equations/chave-2014-eq7/#quote-fit-n-trees

**Largest DBH** (Introduction, p. 3178):

> for a total of 4004 trees with trunk diameter ranging from 5 to 212 cm

Cite: https://treeallometry.org/equations/chave-2014-eq7/#quote-fit-dbh-max-cm

**Our note:** Use when height is not measured. E from Eq. 6b / the authors' gridded layer. Printed as AGBest under the paper's Eq. 2 convention (estimator includes exp(σ²/2)); no further correction applied. Note: the BIOMASS R package uses refitted coefficients for this model, not these printed ones.

## 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, rho = 0.6, E = 0 | 629 | 629 | Computed from the printed form: computed with python3 from the published form |
| D = 30, rho = 0.6, E = 0.5 | 386 | 386 | Computed from the printed form: computed with python3 from the published form |

Cite: https://treeallometry.org/equations/chave-2014-eq7/#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: Chave, J., Réjou-Méchain, M., Búrquez, A., et al. (2014). Improved allometric models to estimate the aboveground biomass of tropical trees. Global Change Biology, 20(10), 3177–3190. https://doi.org/10.1111/gcb.12629

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Pantropical AGB without height, with stress index E (Eq. 7)", checked 2026-11-01, https://treeallometry.org/equations/chave-2014-eq7/. 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/chave-2014-eq7.json
Report a problem: email info@restorationscope.com with the equation id (chave-2014-eq7) and where the right value appears.