Tree Allometrics

Betula pendula / Root biomass

Betula pendula, Germany, belowground biomass from DBH (Eq. 4, Tab. 1)

Root biomassBetula pendula · BetulaceaeGermanymixedRead from the original paper
Photo of Betula pendula
© Douglas Goldman · CC BY-SA · iNaturalist
Equation

As printed (Eq. 4 and Tab. 1, p. 168)

BGB = β1 · DBH^β2; Birch β1 0.04582 (0.0092-0.0824), β2 2.23951 (2.0047-2.4742), ME 0.81, RMSE 26.9

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

Root biomass = 0.04582 * D^2.23951
D
Diameter at breast height (1.3 m), cm

Dry mass of coarse roots (2 mm and thicker) including the belowground stump; fine roots excluded. Units not printed beside Tab. 1 but BGB is reported in kg and DBH in cm throughout the paper. The paper gives model efficiency (ME) and RMSE, not R², so none is recorded.

Source
48 Birches, 39 Oaks and 54 Pines were sampled
Trees measured · Material and methods, Study sites, p. 167
DBH ranged from 7.2 up to 53.2 cm for Pine, from 7.4 to 42.0 cm for Oak and from 8.2 to 52.9 cm for Birch
Largest DBH · Study sites, pp. 167-168
Trees measured
48
DBH range
8.2–52.9 cm
Method
weighted (1/DBH²) nonlinear least squares power function
Where
20 forest stands in Brandenburg, Saxony-Anhalt and Thuringia, Germany
Last checked
2026-11-02
Calculate
7.95
Root biomass (kg)
3.74
Carbon (kg), ×0.47
13.7
CO₂e (kg), ×44/12
Fitted DBH range050100150200510152025303540DBH (cm)Root biomass (kg)Root 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 = 107.957.95Computed from the printed form
hand-computed from the published form
D = 2561.961.9Computed from the printed form
hand-computed from the published form
D = 40177177Computed from the printed form
hand-computed from the published form

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