Tree Allometrics

Tsuga canadensis / Branch biomass

NSVB eastern hemlock, Hot Continental Regime Mountains (M220): branch biomass (wood and bark), Schumacher-Hall model (Eq. 1)

Branch biomassTsuga canadensis · PinaceaeUnited StatesRead from the original paper
Photo of Tsuga canadensis
© Ian Manning · CC BY · iNaturalist
Equation

As printed (Table S7a (Table S7a_branch_biomass_coefs_spcd.csv, WO-GTR-104-Supp1), columns SPCD,DIVISION,STDORGCD,model,a,b,b1,c)

261,M220,,1,2.163238692,2.490148365,,-0.371162316

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

Branch biomass = 0.45359237 * 2.163238692 * (D/2.54)^2.490148365 * (H/0.3048)^(-0.371162316)
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

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). n and the DBH range are from the scorecard for BRT_WDBK_DW_TOT in M220 (table S19).

Source
yi = a × Di^b × Hi^c + εi
Equation · Eq. 1, 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
261,eastern hemlock,N,Tsuga,canadensis,,,Tsuga canadensis
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 branch wood and bark biomass
Output · Methods, Model development, p. 4
"Branches","BRT_WDBK_DW_TOT","261","M220","HOT_CONTINENTAL_REGIME_MOUNTAINS",62,8.24032258064516,1.5,21.7
Fit · Table S19_component_division_spcd_scorecard.csv (WO-GTR-104-Supp1), columns VAR2,VAR3,SPCD,DIVISION,DIVISION_DESCRIPTION,N,Avg_DBH,Min_DBH,Max_DBH
key modeling statistics such as sample sizes (n), tree diameter distributions (minimum, mean, and maximum)
Fit · Methods, Model development, p. 6
Trees measured
62
DBH range
3.81–55.12 cm
Method
NSVB Schumacher-Hall model (Eq. 1), coefficients for SPCD 261 in DIVISION M220 from table S7a; fitted with weighted regression to destructively sampled trees
Where
FIA ecodivision Hot Continental Regime Mountains (M220), mapped in GTR fig. 1
Last checked
2026-11-03
Calculate
Height from
98.7
Branch biomass (kg)
46.4
Carbon (kg), ×0.47
170
CO₂e (kg), ×44/12
Fitted DBH range0100200300400500600102030405060DBH (cm)Branch biomass (kg)Branch biomass

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 = 30.5, H = 21.398.798.7Computed from the printed form
computed from the published form at D = 12 in, H = 70 ft, converted to cm, m and kg

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