{"id":"dorisca-2011-power-d","source":{"id":"dorisca-2011","citation":"Dorisca, S., Durrieu de Madron, L., Fontez, B., Giraud, A., Riera, B. (2011). Établissement d'équations entre le diamètre et le volume total de bois des arbres, adaptées au Cameroun. Bois et Forêts des Tropiques, 308(2), 87-95.","title":"Établissement d'équations entre le diamètre et le volume total de bois des arbres, adaptées au Cameroun","authors":["Dorisca, S.","Durrieu de Madron, L.","Fontez, B."],"year":2011,"venue":"Bois et Forêts des Tropiques","doi":"10.19182/bft2011.308.a20477","url":"https://doi.org/10.19182/bft2011.308.a20477","read_url":"https://revues.cirad.fr/index.php/BFT/article/download/20477/20236","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current","notes":"Read the full open PDF (French). Total wood volume of the tree down to a 1 cm cut-off, in cm3; the paper says biomass = volume x specific density (+ a leaf correction), not given as an equation. Equations (1)-(4) are captured. Equation (5), V = 11195.6 + 4032.6 HDbh2, is not captured: with H and Dbh in the units the Methods give it predicts absurd volumes (about 2.5e10 cm3 for a 50 cm tree with H in cm), so the unit of H for that equation is unclear."},"name":"Cameroon semi-deciduous forest total wood volume, Eq. (3), power in DBH only","output":{"quantity":"total_volume"},"expression":"157.9 * D^2.55 / 1e6","published":{"expression":"157.9 * DBH^2.55 / 1000","units":{"DBH":"cm"},"variables":{"DBH":"D"},"output_unit":"dm3"},"taxon":{"level":"mixed","name":"23 timber species of semi-deciduous forest (mixed)","group":"broadleaf"},"region":{"scope":"regional","countries":["CM"],"place":"Two forest management units (UFA 10-026 and 10-051), south-east Cameroon, about 1,500 mm rain per year","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":55,"dbh_min_cm":10,"dbh_max_cm":120,"r2":0.93,"method":"gls/gnls (nlme in R), variance modelled as a power of DBH; R2 is the generalized R2 (model efficiency)"},"evidence":[{"field":"expression","quote":"V̂ = 157,9 Dbh2,55","locator":"Équation (3), Résultats / Tableau II, pp. 92-95"},{"field":"fit.n_trees","quote":"55 arbres de 10 à 120 cm de diamètre, appartenant à 23 espèces","locator":"Résumé, p. 88"},{"field":"fit.dbh_min_cm","quote":"La plage de validité de ces équations est de 10 à 120 cm.","locator":"Comparaison des cinq modèles, p. 94"},{"field":"fit.r2","quote":"R² généralisé 0,93","locator":"Tableau II, p. 95"},{"field":"units","quote":"Vi désigne le volume total de bois jusqu'à un diamètre découpe de 1 cm (en cm3), Dbhi désigne le diamètre à hauteur de poitrine (en cm) et Hi la hauteur (en cm)","locator":"Méthodes de calcul, p. 91"}],"check":[{"inputs":{"D":20},"expected":0.3281,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":50},"expected":3.3943,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":100},"expected":19.878,"origin":"computed","note":"computed from the published form (coefficients as printed)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Total wood volume of the tree (stem and branches) down to a 1 cm diameter cut-off, not biomass. The paper fits V in cm3 with DBH in cm and, per its Methods, H in cm; the unit list has no cm3, so the published form is divided by 1000 and given in dm3, and the canonical form is divided by 1e6 to give m3 (and H in m is multiplied by 100). The paper says biomass follows from multiplying volume by specific density plus a small foliage correction, but gives no equation, so no biomass equation is stored. Sample 55 trees, DBH over 10 cm, more than 17 above 45 cm. R2 is the generalized R2 of Mayer and Butler (1993)."}