# Oak root biomass from D (Table 3)

Root biomass equation for Quercus (Q. mongolica and Q. wutaishanica), China, from Meng et al. 2021. 53 trees, DBH 1.5–32.8 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

Fitted on Quercus mongolica, Quercus wutaishanica.

## Equation

As printed in Meng et al. 2021 (Table 3, Root, predictor D (selected: "The equation with D as the only predictor was therefore most suitable for root biomass")):

> Root D 0.086*** 2.072***

Cite: https://treeallometry.org/equations/meng-2021-root-d/#equation

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

```
Root biomass = 0.086 * D^2.072
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 0.086 * D^2.072, with D in cm; output in kg.
Cite: https://treeallometry.org/equations/meng-2021-root-d/#canonical

## What it covers

- Output: Root biomass, kg
- Taxon: Quercus (Q. mongolica and Q. wutaishanica) (genus), family Fagaceae; broadleaf
- Where: Daxing'anling, Xiaoxing'anling and Changbai mountains, NE China. Cite: https://treeallometry.org/equations/meng-2021-root-d/#where
- Biomes: temperate, boreal, montane
- Stand: natural
- Trees measured: 53. Cite: https://treeallometry.org/equations/meng-2021-root-d/#n_trees
- DBH range: 1.5–32.8 cm. Cite: https://treeallometry.org/equations/meng-2021-root-d/#dbh
- Method: weighted nonlinear regression (root equations fitted separately). Cite: https://treeallometry.org/equations/meng-2021-root-d/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/meng-2021-root-d/#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

Meng, S., Yang, F., Hu, S., et al. (2021). Generic Additive Allometric Models and Biomass Allocation for Two Natural Oak Species in Northeastern China. Forests, 12(6), 715.

- DOI: https://doi.org/10.3390/f12060715
- Access: open access
- Copy we read: https://www.mdpi.com/1999-4907/12/6/715/htm
- Every equation from this source: https://treeallometry.org/sources/meng-2021/
- Cite: https://treeallometry.org/equations/meng-2021-root-d/#source

## The facts, in the source's words

**Equation** (Table 3, Root, predictor D (selected: "The equation with D as the only predictor was therefore most suitable for root biomass")):

> Root D 0.086*** 2.072***

Cite: https://treeallometry.org/equations/meng-2021-root-d/#equation

**Trees measured** (Section 2.2):

> 53 trees with a D spanning 1.5-32.8 cm were selected for root biomass collection

Cite: https://treeallometry.org/equations/meng-2021-root-d/#quote-fit-n-trees

**Our note:** Root coefficients as listed in Table 3 for model W = b0*D^b1 (Table 3 coefficients; Table 3 caption: regression coefficients with weighting function). Root biomass is root plus stump dry biomass (Section 2.2). 53 excavated trees.

## 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 = 5 | 2.41 | 2.41 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 15 | 23.5 | 23.5 | Computed from the printed form: computed from the published form (coefficients as printed) |
| D = 30 | 98.9 | 98.9 | Computed from the printed form: computed from the published form (coefficients as printed) |

Cite: https://treeallometry.org/equations/meng-2021-root-d/#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: Meng, S., Yang, F., Hu, S., et al. (2021). Generic Additive Allometric Models and Biomass Allocation for Two Natural Oak Species in Northeastern China. Forests, 12(6), 715. https://doi.org/10.3390/f12060715

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Oak root biomass from D (Table 3)", checked 2026-11-02, https://treeallometry.org/equations/meng-2021-root-d/. 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/meng-2021-root-d.json
Report a problem: email info@restorationscope.com with the equation id (meng-2021-root-d) and where the right value appears.