Equations / Root biomass

Guangzhou subtropical forest belowground biomass, Model 3 (DBH and height)

Root biomassSubtropical evergreen broadleaf forest trees (Castanopsis fissa, Aleurites montana, Castanopsis chinensis, Machilus chinensis and 22 companion species)ChinanaturalRead from the original paper

Fitted on these 4 species and others the paper does not name here: Castanopsis fissa, Aleurites montana, Castanopsis chinensis, Machilus chinensis

Photo: (c) Cheng-Tao Lin, sommige rechten voorbehouden (CC BY), geüpload door Cheng-Tao Lin — 2 of the 4 species it was fitted on · iNaturalist photos, hover for credit

Photo: no rights reserved, uploaded by Agnes Trekker — 2 of the 4 species it was fitted on · iNaturalist photos, hover for credit

Equation

As printed (Section 2.4, Eq. 3)

ln(B) = a + bln(DBH²) + cln(H)

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

Root biomass = exp(-3.44 + 1.062 * ln(D^2) + 0.223 * ln(H))

D: Diameter at breast height (1.3 m), cm
H: Total tree height, m

ln(B) = a + bln(DBH²) + cln(H). 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. The diameter range of the belowground subsample is not stated, so none is given.

Source

Zhao, H., Li, Z., Zhou, G., Qiu, Z., & Wu, Z. (2019). Site-Specific Allometric Models for Prediction of Above- and Belowground Biomass of Subtropical Forests in Guangzhou, Southern China. Forests, 10(10), 862.

doi:10.3390/f10100862 · Open access · copy we read

(3) −3.440 ± 0.284 1.062 ± 0.048 0.223 ± 0.181 3.145 0.340 0.917 19.2 37.89 −5.74

Equation · Table 3, Belowground

(3) −3.440 ± 0.284 1.062 ± 0.048 0.223 ± 0.181 3.145 0.340 0.917 19.2 37.89 −5.74

R² · Table 3, Belowground

for a total of 116 trees, including 24 species and 7 diameter classes

Trees measured · Section 2.2

Trees measured: 116
R²: 0.917
Method: ln-ln regression (R, nlme)
Where: Fushan, about 26 km northeast of Guangzhou, Guangdong
Last checked: 2026-11-02

Calculate

DBH (cm)Height (m)

Height from

17.6

Root biomass (kg)

8.26

Carbon (kg), ×0.47

30.3

CO₂e (kg), ×44/12

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%.

Inputs	Expected	We get	From
D = 15, H = 12	17.6	17.6	Computed from the printed form hand-computed from the published form
D = 40, H = 22	162	161	Computed from the printed form hand-computed from the published form

Report a problem with this equation · JSON

Guangzhou subtropical forest belowground biomass, Model 1 (DBH only) · Zhao et al. 2019 · DBH
Guangzhou subtropical forest belowground biomass, Model 5 (DBH and wood density) · Zhao et al. 2019 · DBH + Wood density
Guangzhou subtropical forest aboveground biomass, Model 1 (DBH only) · same paper · Aboveground biomass
Guangzhou subtropical forest aboveground biomass, Model 3 (DBH and height) · same paper · Aboveground biomass
Guangzhou subtropical forest aboveground biomass, Model 5 (DBH and wood density) · same paper · Aboveground biomass
Guangzhou subtropical forest belowground biomass, Model 1 (DBH only) · same paper · Root biomass
Guangzhou subtropical forest belowground biomass, Model 5 (DBH and wood density) · same paper · Root biomass
Guangzhou subtropical forest branch biomass, Model 1 (DBH only) · same paper · Branch biomass
Guangzhou subtropical forest leaf biomass, Model 1 (DBH only) · same paper · Foliage biomass
Guangzhou subtropical forest stem biomass, Model 1 (DBH only) · same paper · Stem biomass

Compare these curves

Guangzhou subtropical forest belowground biomass, Model 3 (DBH and height)

Related