{"id":"brown-1997-dry","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":"Dry tropical zone AGB from DBH (Eq. 3.2.1)","output":{"quantity":"agb"},"expression":"exp(-1.996 + 2.32 * ln(D))","published":{"expression":"exp(-1.996 + 2.32 * 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, dry zone","biomes":["tropical","dryland"]},"stand":"natural","fit":{"n_trees":28,"dbh_min_cm":5,"dbh_max_cm":40,"r2":0.89},"evidence":[{"field":"expression","quote":"Y = exp{-1.996+2.32*ln(D)}","locator":"Eq. 3.2.1, 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":"5-40 | 28 | 0.89","locator":"Eq. 3.2.1 row: range in dbh (cm), number of trees, adjusted r2"}],"check":[{"inputs":{"D":20},"expected":141.75,"origin":"computed","note":"computed with python3 from the published form"}],"verification":"original_read","checked_at":"2026-11-01","notes":"Revised from Brown et al. (1989) for dry forest in India. The primer recommends it for dry zones with rainfall > 900 mm/yr (Eq. 3.2.2, Martinez-Yrizar et al. 1992, for < 900 mm/yr). r2 is the adjusted r² printed in the table. 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."}