Tree Allometrics

Betula papyrifera / Stem biomass

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

Stem biomassBetula papyrifera · BetulaceaeCanadaRead from the original paper
Photo of Betula papyrifera
Dezene Huber · CC0 · iNaturalist
Equation

As printed (Eq. 2)

y wood = β wood1D βwood2 + ewood

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

Stem biomass = 0.0593 * D^2.5026 + 0.0135 * D^2.4053
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
White birch bwood1 0.0593
Equation · Table 3, White birch
bwood2 2.5026
Equation · Table 3, White birch
bbark1 0.0135
Equation · Table 3, White birch
bbark2 2.4053
Equation · Table 3, White birch
White birch 606 16.4±0.4 13.3±0.2 152.0±7.1
Trees measured · Table 2 (No. of trees)
(1.5;43.6) (2.6;23.9) (0.4;1020.8)
Smallest DBH · Table 2, White birch (ranges of dbh, height, total biomass)
Stem 0.0113 0.94 32.2 3.62 0.0009 0.97 23.9 4.27
R² · Table 5, White birch (AdjRSq in the dbh-based set, first block)
Trees measured
606
DBH range
1.5–43.6 cm
R²
0.94
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
125
Stem biomass (kg)
58.8
Carbon (kg), ×0.47
216
CO₂e (kg), ×44/12
Fitted DBH range0100200300400500600700800510152025303540DBH (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 = 20125125Computed from the printed form
computed from the published form at dbh = 20 cm

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