{"id":"segura-2005-btot-eq15","source":{"id":"segura-2005","citation":"Segura, M., & Kanninen, M. (2005). Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica. Biotropica, 37(1), 2–8.","title":"Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica","authors":["Segura, M.","Kanninen, M."],"year":2005,"venue":"Biotropica","doi":"10.1111/j.1744-7429.2005.02027.x","url":"https://doi.org/10.1111/j.1744-7429.2005.02027.x","read_url":"https://www.cifor-icraf.org/publications/pdf_files/articles/ASegura0501.pdf","access":"open","checked_at":"2026-11-02","status":"current"},"name":"Total AGB from DBH and total height (Eq. 15)","output":{"quantity":"agb"},"expression":"1000 * exp(-6.93 + 1.86 * ln(D) + 0.0045 * ln(D) * H)","published":{"expression":"exp(-6.93 + 1.86 * ln(DBH) + 0.0045 * ln(DBH) * H)","units":{"DBH":"cm","H":"m"},"variables":{"DBH":"D"},"output_unit":"Mg"},"taxon":{"level":"mixed","name":"Seven dominant canopy species (Carapa guianensis, Inga coruscans, Laetia procera, Pentaclethra macroloba, Stryphnodendron microstachyum, Tapirira guianensis, Vochysia ferruginea)","group":"broadleaf","members":["Carapa guianensis","Inga coruscans","Laetia procera","Pentaclethra macroloba","Stryphnodendron microstachyum","Tapirira guianensis","Vochysia ferruginea"],"members_complete":true},"region":{"scope":"regional","countries":["CR"],"place":"Tirimbina (Sarapiquí) and Corinto (Guápiles), northern Costa Rica","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":19,"dbh_min_cm":60,"dbh_max_cm":105,"r2":0.87,"method":"Least-squares regression (SAS), r2 is the adjusted coefficient of determination"},"evidence":[{"field":"expression","quote":"ln B tot = c + a ln DBH + b (ln DBH) H; c −6.93 ± 0.91; a 1.86 ± 0.21; b 0.0045 ± 0.00095","locator":"Table 5, Eq. 15"},{"field":"fit.n_trees","quote":"19 individual trees were measured before harvest","locator":"Methods, p. 3"},{"field":"fit.dbh_max_cm","quote":"adjusted well in the interval of diameters sampled (60–105 cm)","locator":"Discussion, p. 7"}],"check":[{"inputs":{"D":80,"H":28},"expected":5886.7549,"origin":"computed","note":"computed from the printed coefficients"}],"verification":"original_read","checked_at":"2026-11-02","notes":"No back-transform correction factor is stated, so none is applied. Only trees with DBH ≥ 60 cm were harvested; the authors warn the models tend to overestimate outside 60-105 cm. Table 5 gives B tot in 'mg/tree', meaning Mg (Table 3 reports total biomass in Mg, mean 6.7 Mg); the canonical expression multiplies by 1000 to give kg. Best-fit biomass model (adjusted R2 0.87) but needs total height."}