Tree Allometrics

Betula alleghaniensis / Stem biomass

Canadian national equation, yellow birch, dbh only (stem wood plus stem bark; Table 3)

Stem biomassBetula alleghaniensis · BetulaceaeCanadaRead from the original paper
Photo of Betula alleghaniensis
© Douglas Goldman · CC BY-SA · iNaturalist
Equation

As printed (Eq. 2)

y wood = β wood1D βwood2 + ewood

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

Stem biomass = 0.1932 * D^2.1569 + 0.0192 * D^2.2475
D
Diameter at breast height (1.3 m), cm

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 βbark2 + e bark
Equation · Eq. 2
Yellow birch bwood1 0.1932
Equation · Table 3, Yellow birch
bwood2 2.1569
Equation · Table 3, Yellow birch
bbark1 0.0192
Equation · Table 3, Yellow birch
bbark2 2.2475
Equation · Table 3, Yellow birch
Yellow birch 280 25.7±0.9 16.4±0.3 494.4±34.4
Trees measured · Table 2 (No. of trees)
(0.8;70.3) (2.7;25.6) (0.1;2951.4)
Smallest DBH · Table 2, Yellow birch (ranges of dbh, height, total biomass)
Stem 4.5487 0.94 95.5 2.03 0.7738 0.95 88.6 2.44
R² · Table 5, Yellow birch (AdjRSq in the dbh-based set, first block)
Trees measured
280
DBH range
0.8–70.3 cm
R²
0.94
Method
Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total
Where
Canada: Newfoundland and Labrador, Ontario, Quebec (ENFOR archival data, early 1980s)
Last checked
2026-11-03
Calculate
140
Stem biomass (kg)
65.7
Carbon (kg), ×0.47
241
CO₂e (kg), ×44/12
Fitted DBH range0100200300400500600700510152025303540DBH (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 = 20140140Computed from the printed form
computed from the published form at dbh = 20 cm

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