Tree Allometrics

Abies balsamea / Stem biomass

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

Stem biomassAbies balsamea · PinaceaeCanadaRead from the original paper
Photo of Abies balsamea
© Douglas Goldman · CC BY-SA · iNaturalist
Equation

As printed (Eq. 3)

y wood = β wood1D βwood2Hβwood3 + ewood

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

Stem biomass = 0.0294 * D^1.8357 * H^0.864 + 0.0053 * D^2.0876 * H^0.5842
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
Balsam fir bwood1 0.0294
Equation · Table 4, Balsam fir
bwood2 1.8357
Equation · Table 4, Balsam fir
bwood3 0.8640
Equation · Table 4, Balsam fir
bbark1 0.0053
Equation · Table 4, Balsam fir
bbark2 2.0876
Equation · Table 4, Balsam fir
bbark3 0.5842
Equation · Table 4, Balsam fir
Balsam fir 639 16.4±0.4 12.2±0.2 103.4±4.7
Trees measured · Table 2 (No. of trees)
(1.5;42.4) (1.6;52.2) (0.5;649.0)
Smallest DBH · Table 2, Balsam fir (ranges of dbh, height, total biomass)
Stem 0.0017 0.96 19.8 4.03 0.0010 0.99 11.6 3.83
R² · Table 5, Balsam fir (AdjRSq in the dbh- and height-based set, second block)
Trees measured
639
DBH range
1.5–42.4 cm
Height range
1.6–52.2 m
R²
0.99
Method
Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total
Where
Canada: Alberta, Manitoba, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec, Saskatchewan (ENFOR archival data, early 1980s)
Last checked
2026-11-03
Calculate
Height from
88
Stem biomass (kg)
41.4
Carbon (kg), ×0.47
152
CO₂e (kg), ×44/12
Fitted DBH range050100150200250300350510152025303540DBH (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 = 158888Computed from the printed form
computed from the published form at dbh = 20 cm, H = 15 m

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