Tree Allometrics

Equations / Total biomass

Guangzhou subtropical forest total biomass, Model 1 (DBH only)

Total biomassSubtropical evergreen broadleaf forest trees (Castanopsis fissa, Aleurites montana, Castanopsis chinensis, Machilus chinensis and 22 companion species)ChinanaturalRead from the original paper
Many species, no single photo
Equation

As printed (Section 2.4, Eq. 1)

ln(B) = a + bln(DBH²)

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

Total biomass = exp(-1.768 + 1.176 * ln(D^2))
D
Diameter at breast height (1.3 m), cm

ln(B) = a + bln(DBH²). Fitted in R (nlme) on ln-transformed biomass; the paper states no back-transform correction factor and none is applied. Aboveground biomass is above a 10 cm stump (stem, branches, leaves); belowground is the root system plus stump. The paper lists five models (1)-(5); model (2) (ln DBH²H) and (4) (ln DBH²WD) are not added here. Sample size and diameter range for the belowground subsample are not stated separately for the total model, so none is given.

Source
(1) −1.768 ± 0.099 1.176 ± 0.017 0.211 0.954 94.9 30.42 −2.26
Equation · Table 3, Total
(1) −1.768 ± 0.099 1.176 ± 0.017 0.211 0.954 94.9 30.42 −2.26
R² · Table 3, Total
R²
0.954
Method
ln-ln regression (R, nlme)
Where
Fushan, about 26 km northeast of Guangzhou, Guangdong
Last checked
2026-11-02
Calculate
99.62
Total biomass (kg)
46.82
Carbon (kg), ×0.47
171.7
CO₂e (kg), ×44/12
02004006008001,0001,200510152025303540DBH (cm)Total biomass (kg)Total 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 = 1599.699.6Computed from the printed form
hand-computed from the published form
D = 401,0011,000Computed from the printed form
hand-computed from the published form

Report a problem with this equation · JSON

Related

Compare these curves