{"id":"brown-1997-moist-power","source":{"id":"brown-1997","citation":"Brown, S. (1997). Estimating Biomass and Biomass Change of Tropical Forests: a Primer. FAO Forestry Paper 134. Rome: Food and Agriculture Organization of the United Nations. ISBN 92-5-103955-0.","title":"Estimating Biomass and Biomass Change of Tropical Forests: a Primer (FAO Forestry Paper 134)","authors":["Brown, S."],"year":1997,"venue":"FAO Forestry Paper 134","url":"https://www.fao.org/4/w4095e/w4095e00.htm","read_url":"https://www.fao.org/4/w4095e/w4095e06.htm","access":"open","checked_at":"2026-11-01","status":"current"},"name":"Moist tropical zone AGB, power law (Eq. 3.2.4)","output":{"quantity":"agb"},"expression":"exp(-2.134 + 2.530 * ln(D))","published":{"expression":"exp(-2.134 + 2.530 * ln(D))","units":{"D":"cm"},"output_unit":"kg"},"taxon":{"level":"mixed","name":"Tropical broadleaf trees (mixed species)","group":"broadleaf"},"region":{"scope":"pantropical","countries":[],"place":"Tropics, moist zone","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":170,"dbh_min_cm":5,"dbh_max_cm":148,"r2":0.97},"evidence":[{"field":"expression","quote":"Y = exp{-2.134+2.530*ln(D)}","locator":"Eq. 3.2.4, Section 3.2.1 table"},{"field":"published.units","quote":"Y= biomass per tree in kg, D = dbh in cm, and BA = basal area in cm2","locator":"Section 3.2.1, biomass regression equations table header"},{"field":"fit.n_trees","quote":"Both equations are based on the same data base; A. J. R. Gillespie, pers. comm. based on a revision of equation in Brown et al. (1989).","locator":"Section 3.2.1 table, footnote b"}],"check":[{"inputs":{"D":30},"expected":646,"origin":"published","note":"Section 3.2.1 worked example, row 3 'Biomass of tree at mid-point of class': 646 kg at 30 cm. The table labels the equation 3.2.3, but its values match Eq. 3.2.4."},{"inputs":{"D":50},"expected":2353,"origin":"published","note":"Same worked example: 2353 kg at 50 cm (labelled Eq. 3.2.3, values match Eq. 3.2.4)."},{"inputs":{"D":30},"expected":646.15,"origin":"computed","note":"computed with python3 from the published form"}],"verification":"original_read","checked_at":"2026-11-01","notes":"The table leaves range and n blank for this row; footnote b says Eqs. 3.2.3 and 3.2.4 are 'based on the same data base', so n and range are taken from the Eq. 3.2.3 row. The primer prefers it over Eq. 3.2.3 up to about 80 cm and warns it rises rapidly at large diameters. r2 is adjusted r². The primer does not say whether a log back-transform correction is included; none applied. Climatic zones per the primer: dry <1500 mm/yr rain with a dry season of several months; moist 1500–4000 mm/yr; wet >4000 mm/yr, lowland conditions only."}