{"id":"romero-2020-mb1-chave-d-rho","source":{"id":"romero-2020","citation":"Romero, F. M. B., Jacovine, L. A. G., Ribeiro, S. C., Torres, C. M. M. E., Silva, L. F. da, Gaspar, R. de O., et al. (2020). Allometric Equations for Volume, Biomass, and Carbon in Commercial Stems Harvested in a Managed Forest in the Southwestern Amazon: A Case Study. Forests, 11(8), 874.","title":"Allometric Equations for Volume, Biomass, and Carbon in Commercial Stems Harvested in a Managed Forest in the Southwestern Amazon: A Case Study","authors":["Romero, F. M. B.","Jacovine, L. A. G.","Ribeiro, S. C."],"year":2020,"venue":"Forests","doi":"10.3390/f11080874","url":"https://doi.org/10.3390/f11080874","read_url":"https://www.mdpi.com/1999-4907/11/8/874/htm","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current","notes":"Equations are for the commercial stem (stump cut at 30 cm, buttresses removed, crown left in the forest), not the whole tree."},"name":"Commercial stem biomass from DBH and wood density (MB1)","output":{"quantity":"stem_biomass"},"expression":"1000 * exp(-6.51456) * D^1.93113 * rho^1.317114 * 1.048296","published":{"expression":"exp(-6.51456) * d^1.93113 * p^1.317114 * 1.048296","units":{"d":"cm","p":"g/cm3"},"variables":{"d":"D","p":"rho"},"output_unit":"Mg"},"taxon":{"level":"mixed","name":"20 commercial tree species of a managed forest (DBH >= 50 cm)","group":"broadleaf"},"region":{"scope":"site","countries":["BR"],"place":"Fazenda Antimari I and II, Porto Acre, Acre","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":223,"dbh_min_cm":50.4,"dbh_max_cm":149.9,"r2":0.78,"cf":1.048296,"method":"Linear regression on ln(B) vs ln(d) and ln(p), back-transformed with correction factor"},"evidence":[{"field":"expression","quote":"ln(B) = β0 + β1 ln(d) + β2 ln(p) + ε","locator":"Table 1, MB1 (Chave et al. 2005 form)"},{"field":"fit.r2","quote":"MB1 −6.51456 * 1.93113 * 1.317114 * 1.296 0.78 753.60 0.857 1.048296","locator":"Table 4 (β0, β1, β2, RMSE, R2, AIC, MAD, CF)"},{"field":"fit.dbh_min_cm","quote":"Total 223 50.4–149.9 79.6 ± 19.8 0.27–0.89 0.56 ± 0.16","locator":"Table 2 (n, DBH range and mean, wood density range and mean)"}],"check":[{"inputs":{"D":60,"rho":0.56},"expected":1965.3,"origin":"computed","note":"computed from the published form (B in Mg times 1000)"},{"inputs":{"D":100,"rho":0.7},"expected":7071,"origin":"computed","note":"computed from the published form (B in Mg times 1000)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"B is in Mg in the paper (methods: biomass in Mg), converted to kg in the canonical form. p is the species mean basic density (g/cm3). Biomass is commercial stem volume times basic density. R2 is on the log scale. Applies to commercial stems only (stump at 30 cm, buttresses removed, crown left in the forest) of trees with DBH >= 50 cm; do not use for whole-tree totals. The authors selected the equations with commercial stem length l as the best ones; these are the ones that use only canonical variables."}