Tree Allometrics

Betula populifolia / Stem biomass

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

Stem biomassBetula populifolia · BetulaceaeCanadaRead from the original paper
Photo of Betula populifolia
© Homer Edward Price · CC BY · iNaturalist
Equation

As printed (Eq. 2)

y wood = β wood1D βwood2 + ewood

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

Stem biomass = 0.072 * D^2.3885 + 0.0168 * D^2.2569
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
Grey birch bwood1 0.0720
Equation · Table 3, Grey birch
bwood2 2.3885
Equation · Table 3, Grey birch
bbark1 0.0168
Equation · Table 3, Grey birch
bbark2 2.2569
Equation · Table 3, Grey birch
Grey birch 43 10.3±0.8 8.9±0.5 39.8±6.9
Trees measured · Table 2 (No. of trees)
(2.2;22.7) (2.3;14.9) (0.6;181.0)
Smallest DBH · Table 2, Grey birch (ranges of dbh, height, total biomass)
Stem 0.0066 0.96 7.3 3.18 0.0035 0.98 4.8 3.11
R² · Table 5, Grey birch (AdjRSq in the dbh-based set, first block)
Trees measured
43
DBH range
2.2–22.7 cm
R²
0.96
Method
Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total
Where
Nova Scotia, Canada (ENFOR archival data, early 1980s)
Last checked
2026-11-03
Calculate
107
Stem biomass (kg)
50.2
Carbon (kg), ×0.47
184
CO₂e (kg), ×44/12
Fitted DBH range0100200300400500600510152025303540DBH (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 = 20107107Computed from the printed form
computed from the published form at dbh = 20 cm

Report a problem with this equation · JSON

Related

Compare these curves