Tree Allometrics

Fraxinus americana / Stem biomass

Canadian national equation, white ash, dbh and height (stem wood plus stem bark; Table 4)

Stem biomassFraxinus americana · OleaceaeCanadaRead from the original paper
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Equation

As printed (Eq. 3)

y wood = β wood1D βwood2Hβwood3 + ewood

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

Stem biomass = 0.0224 * D^1.7438 * H^1.1899 + 0.0126 * D^1.6456 * H^0.7893
D
Diameter at breast height (1.3 m), cm
H
Total tree height, m

Stem from ground level to tree top, stem wood plus stem bark; the stem is the sum of the two compartment equations. 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
y bark = β bark1D βbark2Hβbark3 + e bark
Equation · Eq. 3
White ash bwood1 0.0224
Equation · Table 4, White ash
bwood2 1.7438
Equation · Table 4, White ash
bwood3 1.1899
Equation · Table 4, White ash
bbark1 0.0126
Equation · Table 4, White ash
bbark2 1.6456
Equation · Table 4, White ash
bbark3 0.7893
Equation · Table 4, White ash
White ash 109 22.3±1.1 17.6±0.4 296.2±28.5
Trees measured · Table 2 (No. of trees)
(2.4;53.7) (3.9;26.9) (1.2;1850.1)
Smallest DBH · Table 2, White ash (ranges of dbh, height, total biomass)
Stem 0.0119 0.87 80.3 3.91 0.3561 0.93 57.2 2.60
R² · Table 5, White ash (AdjRSq in the dbh- and height-based set, second block)
Trees measured
109
DBH range
2.4–53.7 cm
Height range
3.9–26.9 m
R²
0.93
Method
Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total
Where
Ontario and Quebec, Canada (ENFOR archival data, early 1980s)
Last checked
2026-11-03
Calculate
Height from
119
Stem biomass (kg)
56
Carbon (kg), ×0.47
205
CO₂e (kg), ×44/12
Fitted DBH range0100200300400510152025303540DBH (cm)Stem biomass (kg)Stem 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 = 15119119Computed from the printed form
computed from the published form at dbh = 20 cm, H = 15 m

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