# Socratea exorrhiza AGB from diameter and stem height

Aboveground biomass equation for Socratea exorrhiza, Peru, from Goodman et al. 2013. 20 trees, DBH 4–24 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Goodman et al. 2013 (Table 3):

> Socratea ln(AGB) ln(D2Hstem) -3.7965 1.0029 0.976 20 0.227

Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#equation

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

```
Aboveground biomass = 1.0261 * exp(-3.7965 + 1.0029 * ln(D^2 * Hstem))
```

Inputs: D = Diameter at breast height (1.3 m) (cm); Hstem = Palm stem height, ground to the lowest leaf (m).
The source's own form: 1.0261 * exp(-3.7965 + 1.0029 * ln(D^2 * Hstem)), with D in cm, Hstem in m; output in kg.
Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Socratea exorrhiza (species), family Arecaceae; palm
- Where: Terra firme moist forest, forestry concession, Madre de Dios, Peru. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#where
- Biomes: tropical
- Stand: natural
- Trees measured: 20. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#n_trees
- DBH range: 4–24 cm. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#dbh
- R²: 0.976. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#r2
- Residual SE: 0.227. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#rse
- Correction factor: 1.0261 (applied). Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#cf
- Method: OLS on ln(AGB) vs ln(D²·Hstem); Baskerville correction exp(RSE²/2). Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#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

Goodman, R. C., Phillips, O. L., del Castillo Torres, D., Freitas, L., Cortese, S. T., Monteagudo, A., & Baker, T. R. (2013). Amazon palm biomass and allometry. Forest Ecology and Management, 310, 994–1004.

- DOI: https://doi.org/10.1016/j.foreco.2013.09.045
- Access: paywalled
- Copy we read: http://eprints.whiterose.ac.uk/77906/7/Amazon%20Palm%20Biomass_Goodman_with_coversheet.pdf
- Every equation from this source: https://treeallometry.org/sources/goodman-2013/
- Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#source

## The facts, in the source's words

**Equation** (Table 3):

> Socratea ln(AGB) ln(D2Hstem) -3.7965 1.0029 0.976 20 0.227

Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#equation

**Smallest DBH** (Table 1):

> MdD Socratea exorrhiza 20 4-24 2.0-21.9 3.2-23.9

Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#quote-fit-dbh-min-cm

**Correction factor** (Section 2.4, lines 220–221 (author post-print)):

> A correction factor, exp(RSE2/2), was applied to biomass estimates from logarithmically transformed models (Baskerville, 1972).

Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#quote-fit-cf

**Our note:** Hstem = stem height to the base of the lowest leaf (m). D at 1.3 m or above the stilt roots. Fitted Hstem range 2.0–21.9 m. Correction factor multiplied in.

## 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, Hstem = 15 | 79.6 | 79.6 | Computed from the printed form: computed from the Table 3 coefficients times exp(RSE²/2) |

Cite: https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/#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: Goodman, R. C., Phillips, O. L., del Castillo Torres, D., Freitas, L., Cortese, S. T., Monteagudo, A., & Baker, T. R. (2013). Amazon palm biomass and allometry. Forest Ecology and Management, 310, 994–1004. https://doi.org/10.1016/j.foreco.2013.09.045

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Socratea exorrhiza AGB from diameter and stem height", checked 2026-11-01, https://treeallometry.org/equations/goodman-2013-socratea-exorrhiza/. 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/goodman-2013-socratea-exorrhiza.json
Report a problem: email info@restorationscope.com with the equation id (goodman-2013-socratea-exorrhiza) and where the right value appears.