{"id":"segura-2005-vstem-lnd","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":"Stem volume from DBH (Eq. 5)","output":{"quantity":"stem_volume"},"expression":"exp(-8.70 + 2.41 * ln(D))","published":{"expression":"exp(-8.70 + 2.41 * ln(DBH))","units":{"DBH":"cm"},"variables":{"DBH":"D"},"output_unit":"m3"},"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":0.66,"method":"Least-squares regression (SAS), r2 is the adjusted coefficient of determination"},"evidence":[{"field":"expression","quote":"ln V stem = c + a ln DBH; c −8.70 ± 1.77; a 2.41 ± 0.40","locator":"Table 4, Eq. 5"},{"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},"expected":6.4281,"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 4 caption labels V stem in Mg/tree, which is a typo: Table 3 gives stem volume in m3 and Eq. 5 at the mean DBH reproduces that scale (about 7 m3). Stem = commercial stem + non-commercial stem + stump."}