# Miombo coarse root biomass, DBH only

Root biomass equation for Miombo woodland trees, Mozambique, from Ryan et al. 2011. 23 trees. 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,r) = 2.262 log(DBH,dest)-3.370

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

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

```
Root biomass = exp(2.262 * ln(D) - 3.370) / 0.47
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(2.262 * ln(DBH) - 3.370) / 0.47, with DBH in cm; output in kg.
Cite: https://treeallometry.org/equations/ryan-2011-root/#canonical

## What it covers

- Output: Root biomass, kg
- Taxon: Miombo woodland trees (mixed species); broadleaf
- Where: Nhambita, Sofala province, Mozambique. Cite: https://treeallometry.org/equations/ryan-2011-root/#where
- Biomes: tropical, dryland
- Stand: natural
- Trees measured: 23. Cite: https://treeallometry.org/equations/ryan-2011-root/#n_trees
- R²: 0.94. Cite: https://treeallometry.org/equations/ryan-2011-root/#r2
- Residual SE: 0.43. Cite: https://treeallometry.org/equations/ryan-2011-root/#rse
- Method: OLS on ln-transformed data, no correction factor. Cite: https://treeallometry.org/equations/ryan-2011-root/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/ryan-2011-root/#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-root/#source

## The facts, in the source's words

**Equation** (Table 1):

> log(Bdest,r) = 2.262 log(DBH,dest)-3.370

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

**Note** (Methods):

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

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

**Our note:** Paper gives kg carbon; divided by the paper's 0.47 carbon fraction to give kg dry mass. No correction factor, as in the paper.

## 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 | 64.2 | 64.2 | Computed from the printed form: hand-computed from the published form |

Cite: https://treeallometry.org/equations/ryan-2011-root/#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 coarse root biomass, DBH only", checked 2026-11-01, https://treeallometry.org/equations/ryan-2011-root/. 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-root.json
Report a problem: email info@restorationscope.com with the equation id (ryan-2011-root) and where the right value appears.