{"id":"djomo-2010-campo-d-d2h-rho","source":{"id":"djomo-2010","citation":"Djomo, A.N., Ibrahima, A., Saborowski, J., Gravenhorst, G. (2010). Allometric equations for biomass estimations in Cameroon and pan moist tropical equations including biomass data from Africa. Forest Ecology and Management, 260(10), 1873–1885.","title":"Allometric equations for biomass estimations in Cameroon and pan moist tropical equations including biomass data from Africa","authors":["Djomo, A.N.","Ibrahima, A.","Saborowski, J."],"year":2010,"venue":"Forest Ecology and Management","doi":"10.1016/j.foreco.2010.08.034","url":"https://doi.org/10.1016/j.foreco.2010.08.034","read_url":"https://uni-goettingen.de/de/document/download/4df40c701547ab5773871feade802dc2.pdf/Djomo_et_al_(2010)_FORECOLMANAG_allometric_equations.pdf","access":"paywalled","checked_at":"2026-11-01","status":"current","notes":"Read from the authors' institutional PDF copy (Georg-August-Universität Göttingen). Seven of the paper's equations are captured: four Campo-Ma'an site equations (Table 3) and three pan moist tropical equations (Table 4). Leaf and branch equations (Table 3), the Table 3/4 variants not listed, and the height-diameter models (Table 6) are not captured."},"name":"Campo-Ma'an AGB from DBH, height and wood density (Table 3, model 5)","output":{"quantity":"agb"},"expression":"exp(-2.3325 + 0.1651 * ln(D)^2 + 0.6620 * ln(D^2 * H) + 0.1309 * ln(rho))","published":{"expression":"exp(-2.3325 + 0.1651 * ln(D)^2 + 0.6620 * ln(D^2 * H) + 0.1309 * ln(WD))","units":{"D":"cm","H":"m","WD":"g/cm3"},"variables":{"WD":"rho"},"output_unit":"kg"},"taxon":{"level":"mixed","name":"Mixed species, Campo-Ma'an lowland moist forest","group":"broadleaf"},"region":{"scope":"site","countries":["CM"],"place":"Campo-Ma'an, southern Cameroon","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":71,"dbh_min_cm":1,"dbh_max_cm":79,"r2":0.9659,"rse":0.291,"method":"log-log regression"},"evidence":[{"field":"expression","quote":"5. ln(M) = a + b(ln D)2 + c ln(D2 H) + β ln(ρ)   a = −2.3325  b = 0.1651  c = 0.6620  (β = 0.1309)","locator":"Table 3, Total biomass, model 5 and footnote a"},{"field":"fit.n_trees","quote":"N 71, RSE 0.291, Adj. R2 0.9659, D (cm) 1–79","locator":"Table 3, model 5"}],"check":[{"inputs":{"D":30,"H":25,"rho":0.64},"expected":470.16,"origin":"computed","note":"hand-computed from the published form"}],"verification":"original_read","checked_at":"2026-11-01","notes":"Best-fitting site equation (lowest RSE, average error 3.4%). Printed form has the intermediate coefficient for ln(D²H) as c and β for ln(ρ) from the table footnote. Coefficients are used as printed; the paper does not state that the log-scale back-transformation correction factor is included, so none is applied. Reported R² is the adjusted R². Table 3 fit on 71 trees (7 of its equations captured). The Discussion (p. 1880) refits on 91 trees and recommends slightly different coefficients, printed without n, RSE or R²; this file keeps the Table 3 fit. The paper notes only three of the 71 trees were above 10 cm. The text calls the best three-variable fit 'model 14' (with a (ln D)³ term), but Table 3 model 5, the only place coefficients are printed, has none; this file follows Table 3."}