Tree Allometrics

Fraxinus nigra / Aboveground biomass

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

Aboveground biomassFraxinus nigra · OleaceaeCanadaRead from the original paper
No openly licensed photo yet
Equation

As printed (Eq. 2)

y wood = β wood1D βwood2 + ewood

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

Aboveground biomass = 0.0941 * D^2.3491 + 0.0323 * D^2.0761 + 0.0448 * D^1.9771 + 0.0538 * D^1.3584
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
Black ash bwood1 0.0941
Equation · Table 3, Black ash
bwood2 2.3491
Equation · Table 3, Black ash
bbark1 0.0323
Equation · Table 3, Black ash
bbark2 2.0761
Equation · Table 3, Black ash
bbranches1 0.0448
Equation · Table 3, Black ash
bbranches2 1.9771
Equation · Table 3, Black ash
bfoliage1 0.0538
Equation · Table 3, Black ash
bfoliage2 1.3584
Equation · Table 3, Black ash
Black ash 73 16.2±1.2 14.4±0.6 142.0±21.6
Trees measured · Table 2 (No. of trees)
(2.0;43.1) (2.6;22.9) (1.0;926.4)
Smallest DBH · Table 2, Black ash (ranges of dbh, height, total biomass)
Total 0.0085 0.96 35.6 3.82 0.1349 0.97 32.9 2.76
R² · Table 5, Black ash (AdjRSq in the dbh-based set, first block)
Trees measured
73
DBH range
2–43.1 cm
R²
0.96
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
143
Aboveground biomass (kg)
67.3
Carbon (kg), ×0.47
247
CO₂e (kg), ×44/12
Fitted DBH range0100200300400500600700510152025303540DBH (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 = 20143143Computed from the printed form
computed from the published form at dbh = 20 cm

Report a problem with this equation · JSON

Related

Compare these curves