# Stem biomass, 18-year secondary montane forest, DAP² only

Stem biomass equation for Secondary montane forest trees, mixed species, Ecuador, from Ramírez et al. 2022. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Ramírez et al. 2022 (Tabla 4, p. 88 (fuste, 18-year)):

> Bf = e^(9,156 + 1,354*ln(Dap²))

Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#equation

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

```
Stem biomass = exp(9.156 + 1.354 * ln((D/100)^2))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(9.156 + 1.354 * ln(Dap^2)), with Dap in m; output in kg.
Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#canonical

## What it covers

- Output: Stem biomass, kg
- Taxon: Secondary montane forest trees, mixed species (mixed species); broadleaf
- Where: Cotacachi, Imbabura, NW Ecuador (1850 m a.s.l.). Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#where
- Biomes: tropical, montane
- Stand: natural
- Method: regression on ln-transformed variables; coefficients as printed. Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#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

Ramírez, J., Córdova, M., Imbaquingo, J., & Chagna, E. (2022). Modelos alométricos para estimar biomasa aérea en bosques secundarios montanos del noroccidente de Ecuador. Caldasia, 44(1), 82–94.

- DOI: https://doi.org/10.15446/caldasia.v44n1.88198
- Access: open access
- Copy we read: https://revistas.unal.edu.co/index.php/cal/article/view/88198
- Every equation from this source: https://treeallometry.org/sources/ramirez-2022/
- Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#source

## The facts, in the source's words

**Equation** (Tabla 4, p. 88 (fuste, 18-year)):

> Bf = e^(9,156 + 1,354*ln(Dap²))

Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#equation

**Our note:** Dap is in metres in the paper (Tabla 4 footnote), Ht in m, biomass in kg; printed as e^(a + b*ln(...)), natural log, no correction factor stated. Per-model adjusted R2 is in Tabla 4 but it is adjusted R2 and the per-model n is not stated, so both left out. Total = stem + branches + leaves. Stand age approx. (owner information).

## 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 = 10 | 18.6 | 18.6 | Computed from the printed form: hand-computed from the published form (Dap in m) |
| D = 25 | 221.8 | 221.8 | Computed from the printed form: hand-computed from the published form (Dap in m) |

Cite: https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/#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: Ramírez, J., Córdova, M., Imbaquingo, J., & Chagna, E. (2022). Modelos alométricos para estimar biomasa aérea en bosques secundarios montanos del noroccidente de Ecuador. Caldasia, 44(1), 82–94. https://doi.org/10.15446/caldasia.v44n1.88198

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Stem biomass, 18-year secondary montane forest, DAP² only", checked 2026-11-02, https://treeallometry.org/equations/ramirez-2022-age18-stem-d2/. 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/ramirez-2022-age18-stem-d2.json
Report a problem: email info@restorationscope.com with the equation id (ramirez-2022-age18-stem-d2) and where the right value appears.