{"id":"gaui-2024-rf-model2","source":{"id":"gaui-2024","citation":"Gaui, T. D., Cysneiros, V. C., de Souza, F. C., et al. (2024). Biomass Equations and Carbon Stock Estimates for the Southeastern Brazilian Atlantic Forest. Forests, 15(9), 1568.","title":"Biomass Equations and Carbon Stock Estimates for the Southeastern Brazilian Atlantic Forest","authors":["Gaui, T. D.","Cysneiros, V. C.","de Souza, F. C."],"year":2024,"venue":"Forests","doi":"10.3390/f15091568","url":"https://doi.org/10.3390/f15091568","read_url":"https://www.mdpi.com/1999-4907/15/9/1568/htm","access":"open","checked_at":"2026-11-02","status":"current"},"name":"Restinga forest, Rio de Janeiro, DBH and height (Spurr, Model 2)","output":{"quantity":"agb","excludes":["foliage"]},"expression":"1000 * (0.05 + 1.83e-05 * D^2 * H)","published":{"expression":"0.05 + 1.83e-05 * DBH^2 * Ht","units":{"DBH":"cm","Ht":"m"},"variables":{"DBH":"D","Ht":"H"},"output_unit":"Mg"},"taxon":{"level":"mixed","name":"Mixed restinga forest trees","group":"broadleaf"},"region":{"scope":"regional","countries":["BR"],"place":"Rio de Janeiro state, Atlantic Forest Domain","biomes":["tropical","subtropical"]},"stand":"natural","fit":{"n_trees":37,"r2":0.8,"method":"non-linear regression, generalised least squares with varPower variance"},"evidence":[{"field":"expression","quote":"Model 2 (Spurr) RF: B0 0.05, B1 1.83 × 10−5","locator":"Table 2 (model forms in Table 1)"},{"field":"fit.n_trees","quote":"37 to RF","locator":"Section 2.3"}],"check":[{"inputs":{"D":15,"H":12},"expected":99.41,"origin":"computed","note":"hand-computed from the published form (Mg x 1000 = kg)"},{"inputs":{"D":40,"H":22},"expected":694.16,"origin":"computed","note":"hand-computed from the published form (Mg x 1000 = kg)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Table 2 gives coefficients only; the model forms are from Table 1 (Husch y = B0 d^B1; Spurr y = B0 + B1 (d2 h); Schumacher and Hall y = B0 d^B1 h^B2), fitted by non-linear GLS with a varPower variance function. Output unit Mg is from the Figure 2 caption (AGB, Mg); the table itself does not state it, and 1000 x converts to kg. AGB was built from non-destructively measured wood volume (stem and branches) times basic wood density, so foliage is excluded. Coefficients are rounded as printed. Fit r2 is the printed Ryy (correlation of real and estimated values). DBH range of the 172 sample trees not stated. Authors chose the Spurr model for restinga because Model 3 coefficients were not significant and the Model 1 B0 was not significant; only Model 2 added."}