Tree Allometrics

Equations / Aboveground biomass

US national species group: Aspen/alder/cottonwood/willow (Table 4)

Aboveground biomassAspen/alder/cottonwood/willow species group (hardwood), United StatesUnited StatesmixedRead from the original paper
Many species, no single photo
Equation

As printed (Table 4 footnote, p. 20)

bm = Exp(β0 + β1 ln dbh)

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

Aboveground biomass = exp(-2.2094 + 2.3867 * ln(D))
D
Diameter at breast height (1.3 m), cm

Group membership: Alnus, Populus and Salix (Table 1); includes Populus deltoides, P. tremuloides and hybrid-poplar parents. dbh_max_cm is the 'Max dbh of trees measured in published equations'; data points are pseudodata, not trees. Hardwood groups were extended to 230 cm dbh with Freedman (1984) pseudodata. No log-bias correction: the authors deliberately omit it; a user could multiply by exp(RMSE²/2) = 1.1374. Superseded for FIA reporting by NSVB (Westfall et al. 2024) but still widely used in carbon protocols.

Source
Aspen/alder/cottonwood/willow −2.2094 2.3867 230 70 0.507441 0.953
Equation · Table 4 row, p. 20
bm = total aboveground biomass (kg) for trees 2.5cm dbh and larger
Smallest DBH · Table 4 footnote, p. 20
Root mean squared error or estimate of the standard deviation of the regression error term in natural log units.
Residual standard error · Table 4 footnote §
we do not include CFs for the reader to use after back-transformation
Correction factor · p. 19, Correction factors
DBH range
2.5–70 cm
R²
0.953
Residual SE
0.507441
Method
OLS on ln-transformed pseudodata (230 points, generally at 5 cm dbh intervals) generated from published equations; no back-transform correction applied
Where
Conterminous United States
Last checked
2026-11-01
Calculate
368
Aboveground biomass (kg)
173
Carbon (kg), ×0.47
634
CO₂e (kg), ×44/12
Fitted DBH range05001,0001,5002,000102030405060DBH (cm)Aboveground biomass (kg)Aboveground 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 = 30368368Computed from the printed form
computed from the published form at dbh = 30 cm
D = 1026.726.7Computed from the printed form
computed from the published form at dbh = 10 cm

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