{"id":"chave-2005-wet-noh","source":{"id":"chave-2005","citation":"Chave, J., Andalo, C., Brown, S., et al. (2005). Tree allometry and improved estimation of carbon stocks and balance in tropical forests. Oecologia, 145(1), 87–99.","title":"Tree allometry and improved estimation of carbon stocks and balance in tropical forests","authors":["Chave, J.","Andalo, C.","Brown, S."],"year":2005,"venue":"Oecologia","doi":"10.1007/s00442-005-0100-x","url":"https://doi.org/10.1007/s00442-005-0100-x","read_url":"https://web.archive.org/web/2024id_/https://pdf.usaid.gov/pdf_docs/PA00KWXN.pdf","access":"paywalled","checked_at":"2026-11-01","status":"current"},"name":"Wet forest AGB without height (Model II)","output":{"quantity":"agb"},"expression":"rho * exp(-1.239 + 1.980 * ln(D) + 0.207 * (ln(D))^2 - 0.0281 * (ln(D))^3)","published":{"expression":"rho * exp(-1.239 + 1.980 * ln(D) + 0.207 * (ln(D))^2 - 0.0281 * (ln(D))^3)","units":{"D":"cm","rho":"g/cm3"},"output_unit":"kg"},"taxon":{"level":"mixed","name":"Tropical broadleaf trees","group":"broadleaf"},"region":{"scope":"pantropical","countries":[],"place":"27 harvest sites across the tropics (America, Asia, Oceania); wet forest stands","biomes":["tropical","montane"]},"stand":"natural","fit":{"dbh_min_cm":5,"dbh_max_cm":156,"rse":0.356,"method":"cubic polynomial in ln(D) plus ln(ρ) with unit coefficient (model II.3)"},"evidence":[{"field":"expression","quote":"⟨AGB⟩est = ρ × exp(−1.239 + 1.980 ln(D) + 0.207(ln(D))² − 0.0281(ln(D))³)","locator":"Choice of the best predictive models, Wet forest stands, p. 93"},{"field":"fit.rse","quote":"Moist −1.562 2.148 – 1,502 0.356 0.996 1,869","locator":"Table 4, model II.3 row (a, b, c, d, b3, df, RSE, r2, AIC; RSE printed once for the joint fit), p. 94"},{"field":"notes","quote":"These equations already include the correction factor (Eq. 7).","locator":"Choice of the best predictive models, p. 93"},{"field":"fit.dbh_max_cm","quote":"The models proposed here are valid in the range 5–156 cm for D, and 50–1,000,000 for ρD²H.","locator":"Recommendations, p. 97"},{"field":"published.units","quote":"D should be measured in centimeter, H in meter, and ρ in grams per cubic meter. The resulting AGB estimated from the equation is then in kilograms.","locator":"Recommendations, p. 97"}],"check":[{"inputs":{"D":30,"rho":0.6},"expected":530.35,"origin":"computed","note":"computed with python3 from the published form"}],"verification":"original_read","checked_at":"2026-11-01","notes":"Printed equation already includes the Baskerville correction factor CF = exp(RSE²/2) (paper's Eq. 7); the paper does not print the CF value, so it is not repeated in fit.cf. RSE is the log-scale RSE of the joint fit across forest types (one value per model in the table). The paper writes 'ρ in grams per cubic meter', a misprint for g/cm³ (it defines wood specific gravity in g/cm³ in Methods). Forest types: dry = evapotranspiration exceeds rainfall more than 5 months/yr (roughly <1,500 mm/yr in lowlands); moist = 1–4-month dry season (ca. 1,500–3,500 mm/yr); wet = less than one dry month (>3,500 mm/yr, or montane cloud forest). Minus signs reconstructed from the PDF text layer, where the minus glyph is lost; intercept signs confirmed against Tables 2/4 (a + RSE²/2). The authors warn this wet-forest model overestimated AGB at a hurricane-affected montane forest with short trees (Blue Mountains, Jamaica)."}