Tree Allometrics

Ulmus americana / Branch biomass

Canadian national equation, white elm, dbh and height (branches; Table 4)

Branch biomassUlmus americana · UlmaceaeCanadaRead from the original paper
Photo of Ulmus americana
Étienne Lacroix-Carignan · CC0 · iNaturalist
Equation

As printed (Eq. 3)

y branches = β branches1D βbranches2Hβbranches3 + e branches

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

Branch biomass = 0.0393 * D^2.188
D
Diameter at breast height (1.3 m), cm

All branches, cut at the stem base (live branches; dead branches excluded). Height drops out of the branches term: the paper leaves its height exponent blank (—, not significantly different from zero). r2 is the adjusted R² (AdjRSq) of this compartment in Table 5. Fitted on the original scale (weighted nonlinear seemingly unrelated regression), so there is no back-transform correction. Dead branches, cones and fruits are not part of aboveground biomass in this work (Materials). Stand type was not always recorded. Ung, Bernier & Guo (2008) later revised parameters for some species with British Columbia data; not used here.

Source
bbranches1 0.0393
Equation · Table 4, White elm
bbranches2 2.1880
Equation · Table 4, White elm
bbranches3 —
Equation · Table 4, White elm
White elm 81 20.3±1.1 13.5±0.5 203.5±28.8
Trees measured · Table 2 (No. of trees)
(0.7;55.2) (2.1;23.2) (0.2;1832.2)
Smallest DBH · Table 2, White elm (ranges of dbh, height, total biomass)
Branches 0.0186 0.76 20.6 3.11 0.0435 0.76 20.6 2.84
R² · Table 5, White elm (AdjRSq in the dbh- and height-based set, second block)
Trees measured
81
DBH range
0.7–55.2 cm
Height range
2.1–23.2 m
R²
0.76
Method
Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total
Where
Ontario, Canada (ENFOR archival data, early 1980s)
Last checked
2026-11-03
Calculate
27.6
Branch biomass (kg)
13
Carbon (kg), ×0.47
47.6
CO₂e (kg), ×44/12
Fitted DBH range020406080100120140510152025303540DBH (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 = 20, H = 1527.627.6Computed from the printed form
computed from the published form at dbh = 20 cm, H = 15 m

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