# NSVB white oak, Hot Continental Mountains (M220), segmented model, D < 11 in (27.94 cm)

Aboveground biomass equation (without leaves) for Quercus alba, United States, from Westfall et al. 2024. DBH up to 27.94 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Westfall et al. 2024 (Example 4, p. 24):

> AGBPredicted = 0.024470323124 × 11^(1.93799905037 – 1.886819489967) × 18.1^1.886819489967 × 65^1.403264431619 = 2285.319903933610

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#equation

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

```
Aboveground biomass, without leaves = 0.45359237 * 0.024470323124 * (D/2.54)^1.93799905037 * (H/0.3048)^1.403264431619
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 0.024470323124 * DBH^1.93799905037 * HT^1.403264431619, with DBH in in, HT in ft; output in lb.
Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#canonical

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

## What it covers

- Output: Aboveground biomass, without leaves, kg
- Taxon: Quercus alba (species), family Fagaceae; broadleaf
- Where: FIA ecodivision M220, Hot Continental Mountains (Appalachian/Ozark highlands). Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#where
- Biomes: temperate, montane
- Stand: mixed
- DBH range: up to 27.94 cm. Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#dbh
- Method: NSVB segmented model (Eq. 2), lower branch; same coefficients a, b, c as printed in Example 4. Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#method
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#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

Westfall, J.A., Coulston, J.W., Gray, A.N., Shaw, J.D., Radtke, P.J., Walker, D.M., Weiskittel, A.R., et al. (2024). A national-scale tree volume, biomass, and carbon modeling system for the United States. Gen. Tech. Rep. WO-104. Washington, DC: USDA Forest Service. 37 p.

- DOI: https://doi.org/10.2737/WO-GTR-104
- Access: open access
- Copy we read: https://research.fs.usda.gov/download/treesearch/66998.pdf
- Every equation from this source: https://treeallometry.org/sources/westfall-2024/
- Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#source

## The facts, in the source's words

**Equation** (Example 4, p. 24):

> AGBPredicted = 0.024470323124 × 11^(1.93799905037 – 1.886819489967) × 18.1^1.886819489967 × 65^1.403264431619 = 2285.319903933610

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#equation

**Taxon** (Example 4, p. 21):

> a live white oak (Quercus alba; SPCD = 802) tree having D = 18.1 inches, H = 65 feet

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#quote-taxon

**Where** (Example 4, p. 21):

> growing in the Hot Continental Mountains (DIVISION = M220)

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#quote-region

**Equation** (Methods, Model development, p. 2):

> k is a set segmentation point that is 9.0 inches for softwoods (SPCD<300) and 11.0 inches for hardwoods (SPCD≥300)

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#quote-expression

**Units** (Methods, p. 2):

> Di is diameter (inches) at breast height (4.5 feet), Hi is total tree height (feet)

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#quote-published-units

**Equation** (Eq. 2, p. 2):

> yi = a × Di^b × Hi^c + εi; Di < k

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#quote-expression-2

**Our note:** Lower branch of the segmented model (D < 11 in = 27.94 cm). The GTR does not print a worked value for this branch; the check is computed. a, b and c are the values printed in Example 4 (b = 1.93799905037 is the exponent inside k^(b−b1)). dbh_max_cm is the segmentation point, not a data range. Same output definition and unit conversions as the large-tree branch.

## 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 = 20.32, H = 15.24 | 151 | 151 | Computed from the printed form: computed from the published form at D = 8 in (20.32 cm), H = 50 ft (15.24 m), converted lb→kg |

Cite: https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/#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: Westfall, J.A., Coulston, J.W., Gray, A.N., Shaw, J.D., Radtke, P.J., Walker, D.M., Weiskittel, A.R., et al. (2024). A national-scale tree volume, biomass, and carbon modeling system for the United States. Gen. Tech. Rep. WO-104. Washington, DC: USDA Forest Service. 37 p. https://doi.org/10.2737/WO-GTR-104

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "NSVB white oak, Hot Continental Mountains (M220), segmented model, D < 11 in (27.94 cm)", checked 2026-11-01, https://treeallometry.org/equations/westfall-2024-quercus-alba-m220-small/. 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/westfall-2024-quercus-alba-m220-small.json
Report a problem: email info@restorationscope.com with the equation id (westfall-2024-quercus-alba-m220-small) and where the right value appears.