Tree Allometrics

Fraxinus americana / Aboveground biomass

Canadian national equation, white ash, dbh only (sum of wood, bark, branches, foliage; Table 3)

Aboveground biomassFraxinus americana · OleaceaeCanadaRead from the original paper
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Equation

As printed (Eq. 2)

y wood = β wood1D βwood2 + ewood

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

Aboveground biomass = 0.1861 * D^2.1665 + 0.0406 * D^1.9946 + 0.0461 * D^2.2291 + 0.1106 * D^1.2277
D
Diameter at breast height (1.3 m), cm

Total aboveground biomass = wood + bark + branches + foliage, each fitted as its own equation; the total is their sum (additivity by construction). 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 βbark2 + e bark
Equation · Eq. 2
y branches = β branches1D βbranches2 + e branches
Equation · Eq. 2
y foliage = β foliage1D βfoliage2 + efoliage
Equation · Eq. 2
White ash bwood1 0.1861
Equation · Table 3, White ash
bwood2 2.1665
Equation · Table 3, White ash
bbark1 0.0406
Equation · Table 3, White ash
bbark2 1.9946
Equation · Table 3, White ash
bbranches1 0.0461
Equation · Table 3, White ash
bbranches2 2.2291
Equation · Table 3, White ash
bfoliage1 0.1106
Equation · Table 3, White ash
bfoliage2 1.2277
Equation · Table 3, 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)
Total 0.0363 0.91 91.0 3.62 0.0491 0.93 78.5 3.38
R² · Table 5, White ash (AdjRSq in the dbh-based set, first block)
Trees measured
109
DBH range
2.4–53.7 cm
R²
0.91
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
180
Aboveground biomass (kg)
84.4
Carbon (kg), ×0.47
309
CO₂e (kg), ×44/12
Fitted DBH range0200400600800510152025303540DBH (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 = 20180180Computed from the printed form
computed from the published form at dbh = 20 cm

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