{"id":"zhao-2019-stem-model1","source":{"id":"zhao-2019","citation":"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.","title":"Site-Specific Allometric Models for Prediction of Above- and Belowground Biomass of Subtropical Forests in Guangzhou, Southern China","authors":["Zhao, H.","Li, Z.","Zhou, G."],"year":2019,"venue":"Forests","doi":"10.3390/f10100862","url":"https://doi.org/10.3390/f10100862","read_url":"https://www.mdpi.com/1999-4907/10/10/862/pdf?version=1571725313","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current"},"name":"Guangzhou subtropical forest stem biomass, Model 1 (DBH only)","output":{"quantity":"stem_biomass"},"expression":"exp(-2.202 + 1.138 * ln(D^2))","published":{"expression":"exp(-2.202 + 1.138 * ln(DBH^2))","units":{"DBH":"cm"},"variables":{"DBH":"D"},"output_unit":"kg"},"taxon":{"level":"mixed","name":"Subtropical evergreen broadleaf forest trees (Castanopsis fissa, Aleurites montana, Castanopsis chinensis, Machilus chinensis and 22 companion species)","group":"broadleaf","members":["Castanopsis fissa","Aleurites montana","Castanopsis chinensis","Machilus chinensis"],"members_complete":false},"region":{"scope":"site","countries":["CN"],"place":"Fushan, about 26 km northeast of Guangzhou, Guangdong","biomes":["subtropical"]},"stand":"natural","fit":{"n_trees":144,"dbh_min_cm":4.2,"dbh_max_cm":61.2,"r2":0.933,"method":"ln-ln regression (R, nlme)"},"evidence":[{"field":"expression","quote":"ln(B) = a + bln(DBH²)","locator":"Section 2.4, Eq. 1"},{"field":"expression","quote":"(1) −2.202 ± 0.1 1.138 ± 0.017 0.529 0.933 53.8 35.02 −2.65","locator":"Table A1, Stem"},{"field":"fit.r2","quote":"(1) −2.202 ± 0.1 1.138 ± 0.017 0.529 0.933 53.8 35.02 −2.65","locator":"Table A1, Stem"},{"field":"fit.n_trees","quote":"a total of 144 sampled trees","locator":"Section 2.2"},{"field":"fit.dbh_min_cm","quote":"Total 4.2 61.2","locator":"Table 1"}],"check":[{"inputs":{"D":15},"expected":52.537,"origin":"computed","note":"hand-computed from the published form"},{"inputs":{"D":40},"expected":489.75,"origin":"computed","note":"hand-computed from the published form"}],"verification":"original_read","checked_at":"2026-11-02","notes":"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."}