# Miombo stem biomass (trunk and branches), DBH only

Aboveground biomass equation (without leaves) for Miombo woodland trees, Mozambique, from Ryan et al. 2011. 29 trees, DBH 5–73 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Ryan et al. 2011 (Table 1):

> log(Bdest,s) = 2.601 log(DBH,dest)-3.629

Cite: https://treeallometry.org/equations/ryan-2011-stem/#equation

In this library's units, ready to compute (aboveground biomass, without leaves in kg):

```
Aboveground biomass, without leaves = exp(2.601 * ln(D) - 3.629) / 0.47
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(2.601 * ln(DBH) - 3.629) / 0.47, with DBH in cm; output in kg.
Cite: https://treeallometry.org/equations/ryan-2011-stem/#canonical

This total leaves out leaves (foliage), as the source defines it.

## What it covers

- Output: Aboveground biomass, without leaves, kg
- Taxon: Miombo woodland trees (mixed species); broadleaf
- Where: Nhambita, Sofala province, Mozambique. Cite: https://treeallometry.org/equations/ryan-2011-stem/#where
- Biomes: tropical, dryland
- Stand: natural
- Trees measured: 29. Cite: https://treeallometry.org/equations/ryan-2011-stem/#n_trees
- DBH range: 5–73 cm. Cite: https://treeallometry.org/equations/ryan-2011-stem/#dbh
- R²: 0.93. Cite: https://treeallometry.org/equations/ryan-2011-stem/#r2
- Residual SE: 0.52. Cite: https://treeallometry.org/equations/ryan-2011-stem/#rse
- Method: OLS on ln-transformed data, no correction factor. Cite: https://treeallometry.org/equations/ryan-2011-stem/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/ryan-2011-stem/#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

Ryan, C.M., Williams, M., Grace, J. (2011). Above- and Belowground Carbon Stocks in a Miombo Woodland Landscape of Mozambique. Biotropica, 43(4), 423–432.

- DOI: https://doi.org/10.1111/j.1744-7429.2010.00713.x
- Access: paywalled
- Copy we read: http://web.archive.org/web/20190427125852id_/https://www.research.ed.ac.uk/portal/files/16641514/C_stock_overview_v13_w_proofs.pdf
- Every equation from this source: https://treeallometry.org/sources/ryan-2011/
- Cite: https://treeallometry.org/equations/ryan-2011-stem/#source

## The facts, in the source's words

**Equation** (Table 1):

> log(Bdest,s) = 2.601 log(DBH,dest)-3.629

Cite: https://treeallometry.org/equations/ryan-2011-stem/#equation

**DBH range** (Results, Tree stem and root biomass):

> The 29 sampled trees ranged in DBH from 5-73 cm.

Cite: https://treeallometry.org/equations/ryan-2011-stem/#quote-fit-dbh

**Note** (Methods):

> the mean (47%±0.20) was used for all conversions to C mass

Cite: https://treeallometry.org/equations/ryan-2011-stem/#quote-notes

**Our note:** The paper's equation gives kg carbon (log is natural log). Converted here to kg dry mass by dividing by the paper's mean carbon fraction 0.47; that division is in both expressions. Stem biomass covers trunk and branches; leaves are not included, so it slightly underestimates total AGB. Back-transformed without a correction factor, as the authors did.

## 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 = 20 | 136.7 | 136.7 | Computed from the printed form: hand-computed from the published form |
| D = 50 | 1,482 | 1,482 | Computed from the printed form: hand-computed from the published form |

Cite: https://treeallometry.org/equations/ryan-2011-stem/#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: Ryan, C.M., Williams, M., Grace, J. (2011). Above- and Belowground Carbon Stocks in a Miombo Woodland Landscape of Mozambique. Biotropica, 43(4), 423–432. https://doi.org/10.1111/j.1744-7429.2010.00713.x

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Miombo stem biomass (trunk and branches), DBH only", checked 2026-11-01, https://treeallometry.org/equations/ryan-2011-stem/. 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/ryan-2011-stem.json
Report a problem: email info@restorationscope.com with the equation id (ryan-2011-stem) and where the right value appears.