Tree Allometrics

Pinus contorta / Branch biomass

Lodgepole pine branch biomass, simple SUR (D only)

Branch biomassPinus contorta · PinaceaeUnited StatesmixedRead from the original paper
Photo of Pinus contorta
© Alison Northup · CC BY · iNaturalist
Equation

As printed (Eqs. 2-5 (X1 = ln DBH) and Table 3, Simple SUR, Lodgepole pine)

Branch = exp(a31 + a32*X1); a31 = -3.384, a32 = 2.202

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

Branch biomass = exp(-3.384 + 2.202 * ln(D))
D
Diameter at breast height (1.3 m), cm

Read from the author's accepted manuscript (draft, manuscript ID cjfr-2015-0256.R1), not the typeset article; values may differ from the final print. Fitted in original scale (nonlinear SUR), so no log back-transform correction. DBH in cm, biomass in kg (Eq. 2-5 text). Extended SUR models using height and crown length are not included (crown length is not a canonical variable).

Source
22 Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and 33 lodgepole pine (Pinus contorta) trees
Trees measured · Materials and Methods, Data and Study Area
Trees measured
33
DBH range
13.5–42.9 cm
Method
seemingly unrelated regression (simple SUR), component equations constrained to sum to total, fitted in original scale
Where
Oregon, USA (several forests)
Last checked
2026-11-02
Calculate
13.2
Branch biomass (kg)
6.2
Carbon (kg), ×0.47
22.7
CO₂e (kg), ×44/12
Fitted DBH range020406080100120510152025303540DBH (cm)Branch biomass (kg)Branch 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 = 1513.213.2Computed from the printed form
computed from the published form (coefficients as printed)
D = 2540.640.6Computed from the printed form
computed from the published form (coefficients as printed)
D = 40114114Computed from the printed form
computed from the published form (coefficients as printed)

Report a problem with this equation · JSON

Related

Compare these curves