{"id":"tipu-2021-agb-d2h","source":{"id":"tipu-2021","citation":"Tipu, M. T. K., Manzoor Rashid, A. Z. M., Tahasina, C., & Mahmood, H. (2021). Semi-destructive approach in developing allometric biomass for Chukrasia tabularis in Sylhet region of Bangladesh. Journal of Tropical Forest Science, 33(2), 203–212.","title":"Semi-destructive approach in developing allometric biomass for Chukrasia tabularis in Sylhet region of Bangladesh","authors":["Tipu, M. T. K.","Manzoor Rashid, A. Z. M.","Tahasina, C."],"year":2021,"venue":"Journal of Tropical Forest Science","doi":"10.26525/jtfs2021.33.2.203","url":"https://doi.org/10.26525/jtfs2021.33.2.203","read_url":"https://web.archive.org/web/2024/https://info.frim.gov.my/infocenter_applications/jtfsonline/jtfs/v33n2/203-212.pdf","access":"open","checked_at":"2026-11-02","status":"current"},"name":"C. tabularis AGB from D2H (Model 7, bias-corrected)","output":{"quantity":"agb"},"expression":"exp(-3.571 + 1.006 * ln(D^2 * H)) * 1.029","published":{"expression":"exp(-3.571 + 1.006 * ln(DBH^2 * H)) * 1.029","units":{"DBH":"cm","H":"m"},"variables":{"DBH":"D"},"output_unit":"kg"},"taxon":{"level":"species","name":"Chukrasia tabularis","family":"Meliaceae","group":"broadleaf"},"region":{"scope":"site","countries":["BD"],"place":"Rema-Kalenga Wildlife Sanctuary, Sylhet region, Bangladesh","biomes":["tropical"]},"stand":"natural","fit":{"n_trees":98,"dbh_min_cm":9,"dbh_max_cm":52,"h_min_m":9,"h_max_m":37,"r2":0.96,"rse":0.243,"cf":1.029,"method":"log-log regression (natural log) with Sprugel correction factor; semi-destructive"},"evidence":[{"field":"expression","quote":"Ln (TAGB) = -3.571 + 1.006 × Ln (D2 × H)","locator":"Results, Allometric models for total aboveground biomass (Model 7, Table 4), p. 208"},{"field":"fit.cf","quote":"7 -3.571 1.006 ... 1.029","locator":"Table 4, Model 7 row (CF column 1.029)"},{"field":"fit.n_trees","quote":"In the first event, 98 individuals were chosen to derive the allometric model, covering diameter at breast height and total height range of 9–52 cm and 9–37 m respectively.","locator":"Sampling and measurement of sample trees, p. 204"},{"field":"fit.dbh_min_cm","quote":"diameter at breast height (9–52 cm) and total height (9–37 m)","locator":"Discussion, p. 208"}],"check":[{"inputs":{"D":15,"H":15},"expected":102.5636,"origin":"computed","note":"computed from the published form (exp of the printed log-log equation times the printed CF 1.029)"},{"inputs":{"D":30,"H":22},"expected":608.1279,"origin":"computed","note":"computed from the published form (exp of the printed log-log equation times the printed CF 1.029)"},{"inputs":{"D":45,"H":30},"expected":1878.4401,"origin":"computed","note":"computed from the published form (exp of the printed log-log equation times the printed CF 1.029)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Adjusted R2 0.960 and RSE 0.243 as printed for Model 7 in Table 4 (RSE is on the log scale). The paper also prints the final back-transformed form as TAGB = 0.028953 × (D2 × H)^1.006 and a bias-corrected 0.029821 × (D2 × H)^1.006; these two coefficients are not consistent with exp(-3.571) = 0.02813 (0.028953 is close to exp(-3.571) × 1.029, and 0.029821 looks like the correction applied twice). This record uses the printed log-log equation with the printed CF 1.029 (coefficient 0.02894); the paper's 0.029821 form gives about 3% more biomass. Sample was 98 trees for model development (n_trees) plus 22 for validation (120 in total), per the Sampling section, p. 204."}