# NSVB loblolly pine (natural stands), Subtropical Division (230): foliage biomass, segmented model (Eq. 2), D < 9 in (22.86 cm)

Foliage biomass equation for Pinus taeda, United States, from Westfall et al. 2024. DBH up to 22.86 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 (Table S9a (Table S9a_foliage_coefs_spcd.csv, WO-GTR-104-Supp1), columns SPCD,DIVISION,STDORGCD,model,a,a1,b,b1,c,c1):

> 131,230,0,2,8.337502275,,2.388420508,2.62020608,-1.119388616,

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#equation

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

```
Foliage biomass = 0.45359237 * 8.337502275 * (D/2.54)^2.388420508 * (H/0.3048)^(-1.119388616)
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: 8.337502275 * DBH^2.388420508 * HT^(-1.119388616), with DBH in in, HT in ft; output in lb.
Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#canonical

## What it covers

- Output: Foliage biomass, kg
- Taxon: Pinus taeda (species), family Pinaceae; conifer
- Where: FIA ecodivision Subtropical Division (230), mapped in GTR fig. 1. Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#where
- Biomes: subtropical
- Stand: natural
- DBH range: up to 22.86 cm. Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#dbh
- Method: NSVB segmented model (Eq. 2), coefficients for SPCD 131 in DIVISION 230, STDORGCD 0 from table S9a; fitted with weighted regression to destructively sampled trees. Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#method
- Verification: read in the original source
- Last checked: 2026-11-03. Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-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-pinus-taeda-230-natural-foliage-small/#source

## The facts, in the source's words

**Equation** (Table S9a (Table S9a_foliage_coefs_spcd.csv, WO-GTR-104-Supp1), columns SPCD,DIVISION,STDORGCD,model,a,a1,b,b1,c,c1):

> 131,230,0,2,8.337502275,,2.388420508,2.62020608,-1.119388616,

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#equation

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

> yi = a × Di^b × Hi^c + εi; Di < k / yi = a × k^(b−b1) × Di^b1 × Hi^c + εi; Di ≥ k

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#quote-expression

**Units** (Methods, Model development, 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-pinus-taeda-230-natural-foliage-small/#quote-published-units

**published.output unit** (Examples of tree-level calculations, p. 8):

> units for volume and biomass predictions are cubic feet and pounds, respectively

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#quote-published-output-unit

**Taxon** (FIADB REF_SPECIES.csv (FIA DataMart), columns SPCD,COMMON_NAME,SHARED_COMMON_NAME_IND,GENUS,SPECIES,VARIETY,SUBSPECIES,SCIENTIFIC_NAME: the species codes the NSVB tables use):

> 131,loblolly pine,N,Pinus,taeda,,,Pinus taeda

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#quote-taxon

**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-pinus-taeda-230-natural-foliage-small/#quote-expression-2

**stand** (Methods, Model development, p. 3):

> stand origins for planted (stand origin code (STDORGCD) = 1) and natural (STDORGCD = 0) stands may be fitted separately

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-small/#quote-stand

**Our note:** DBH is measured at 4.5 ft (1.37 m). Paper units: in, ft, lb; expression converts D cm→in (/2.54), H m→ft (/0.3048) and lb→kg (×0.45359237). The scorecards don't split loblolly and slash pine by stand origin, so n and DBH range are left out. The DBH upper limit is the segmentation point k, not a data range. Lower branch of the segmented model; pair with westfall-2024-pinus-taeda-230-natural-foliage-large.

## 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 = 15.24, H = 13.716 | 3.85 | 3.85 | Computed from the printed form: computed from the published form at D = 6 in, H = 45 ft, converted to cm, m and kg |

Cite: https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-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 loblolly pine (natural stands), Subtropical Division (230): foliage biomass, segmented model (Eq. 2), D < 9 in (22.86 cm)", checked 2026-11-03, https://treeallometry.org/equations/westfall-2024-pinus-taeda-230-natural-foliage-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-pinus-taeda-230-natural-foliage-small.json
Report a problem: email info@restorationscope.com with the equation id (westfall-2024-pinus-taeda-230-natural-foliage-small) and where the right value appears.