Tree Allometrics

Equations / Stem biomass

Multi-species short-stature trees stem biomass, cross-sectional area at 0.3 m (LLRC)

Stem biomassMulti-species short-stature trees (all tree genera/species sampled)CanadanaturalRead from the original paper
Many species, no single photo
Equation

As printed (Table 3, Eqs. 2-5)

Multi-species short-stature trees Stems LLRC 3.833 46.2009 1.109 1.1296 0.939 (columns: ln(β), β, α, CF, RMSE, R2); y = βx^α + ε (Eq. 2); y = βx^α × ε (Eq. 4), ε = e^(MSE/2) (Eq. 5)

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

Stem biomass = 46.2009 * 1.1296 * (0.785398163397448 * D30^2)^1.109 / 1000
D30
Stem diameter at 30 cm, cm

Paper's predictor is cross-sectional area (cm2) of the stem(s) at 0.3 m; converted here to D30 as pi/4 * D30^2 (pi written as 0.785398163397448 * ...), so for multi-stemmed trees D30 is the equivalent diameter of the summed cross-sectional area. Paper output is in g dry mass; canonical form divides by 1000. LLRC correction factor applied as printed in the CF column. Fit range of the predictor is not stated, so none is given.

Source
A total of 206 shrub and 105 tree individuals were measured and destructively sampled at 65 different peatland and forest sites.
Trees measured · Section 2.2
Trees measured
105
R²
0.939
Correction factor
1.1296 (applied)
Method
linear log regression with correction factor (LLRC), y = β x^α × CF, x = cross-sectional area
Where
Sporadic to discontinuous permafrost zone, Taiga Plains and Taiga Shield ecozones, northwestern Canada
Last checked
2026-11-02
Calculate
0.186
Stem biomass (kg)
0.0873
Carbon (kg), ×0.47
0.32
CO₂e (kg), ×44/12
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
D30 = 20.1860.186Computed from the printed form
computed from the published form (coefficients as printed)
D30 = 51.421.42Computed from the printed form
computed from the published form (coefficients as printed)
D30 = 84.024.02Computed from the printed form
computed from the published form (coefficients as printed)

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