Tree Allometrics

Pinus elliottii / Stem volume

NSVB slash pine (natural stands), Subtropical Division (230): total stem wood volume (inside bark), segmented model (Eq. 2), D < 9 in (22.86 cm)

Stem volumePinus elliottii · PinaceaeUnited StatesnaturalRead from the original paper
Photo of Pinus elliottii
Jean-Paul Boerekamps · CC0 · iNaturalist
Equation

As printed (Table S1a (Table S1a_volib_coefs_spcd.csv, WO-GTR-104-Supp1), columns SPCD,DIVISION,STDORGCD,model,a,a1,b,b1,c,c1)

111,230,0,2,0.001206001,,2.141422639,1.948751732,1.068957337,

In this library's units, ready to compute (m³)

Stem volume = 0.028316846592 * 0.001206001 * (D/2.54)^2.141422639 * (H/0.3048)^1.068957337
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Output is gross total stem wood volume inside bark, groundline to tip (VtotibGross), before cull or broken-top deductions. DBH is measured at 4.5 ft (1.37 m). Paper units: in, ft, ft3; expression converts D cm→in (/2.54), H m→ft (/0.3048) and ft3→m3 (×0.028316846592). 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-elliottii-230-natural-volume-large.

Source
yi = a × Di^b × Hi^c + εi; Di < k / yi = a × k^(b−b1) × Di^b1 × Hi^c + εi; Di ≥ k
Equation · Eq. 2, p. 2
Di is diameter (inches) at breast height (4.5 feet), Hi is total tree height (feet)
Units · Methods, Model development, p. 2
units for volume and biomass predictions are cubic feet and pounds, respectively
published.output unit · Examples of tree-level calculations, p. 8
111,slash pine,N,Pinus,elliottii,,,Pinus elliottii
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
total stem was defined as groundline to tree tip
Output · Methods, Data, 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)
Equation · Methods, Model development, p. 2
stand origins for planted (stand origin code (STDORGCD) = 1) and natural (STDORGCD = 0) stands may be fitted separately
stand · Methods, Model development, p. 3
DBH range
up to 22.86 cm
Method
NSVB segmented model (Eq. 2), coefficients for SPCD 111 in DIVISION 230, STDORGCD 0 from table S1a; fitted with weighted regression to destructively sampled trees
Where
FIA ecodivision Subtropical Division (230), mapped in GTR fig. 1
Last checked
2026-11-03
Calculate
Height from
0.0927
Stem volume (m³)
Fitted DBH range00.10.20.30.40.50.60.70.8510152025303540DBH (cm)Stem volume (m³)Stem volume

Shaded: the DBH range the model was fitted on. Other inputs held at the values above.

Checks this equation passes

On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.

InputsExpectedWe getFrom
D = 15.2, H = 13.70.09270.0927Computed from the printed form
computed from the published form at D = 6 in, H = 45 ft, converted to cm, m and m3

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