{"id":"pathibang-2026-branch-quadratic","source":{"id":"pathibang-2026","citation":"Pathibang, M.R., Ora, Y.A.N.R., Almuqu, A.A., et al. (2026). Allometric Biomass Equation Model of Sonneratia alba in Tanah Merah Mangrove Forest, Kupang, East Nusa Tenggara, Indonesia. Jurnal Penelitian Pendidikan IPA, 12(5), 906-915.","title":"Allometric Biomass Equation Model of Sonneratia alba in Tanah Merah Mangrove Forest, Kupang, East Nusa Tenggara, Indonesia","authors":["Pathibang, M.R.","Ora, Y.A.N.R.","Almuqu, A.A."],"year":2026,"venue":"Jurnal Penelitian Pendidikan IPA","doi":"10.29303/jppipa.v12i5.15100","url":"https://doi.org/10.29303/jppipa.v12i5.15100","read_url":"https://jppipa.unram.ac.id/index.php/jppipa/article/download/15100/10027","access":"open","checked_at":"2026-11-02","status":"current"},"name":"Sonneratia alba branch biomass, quadratic model (D)","output":{"quantity":"branch_biomass"},"expression":"287.956 - 36.906 * D + 1.157 * D^2","published":{"expression":"287.956 - 36.906 * D + 1.157 * D^2","units":{"D":"cm"},"output_unit":"kg"},"taxon":{"level":"species","name":"Sonneratia alba","group":"mangrove"},"region":{"scope":"site","countries":["ID"],"place":"Tanah Merah Mangrove Forest, Kupang, East Nusa Tenggara","biomes":["tropical","mangrove"]},"stand":"natural","fit":{"n_trees":8,"r2":0.705,"method":"quadratic model B = a + bD + cD^2"},"evidence":[{"field":"expression","quote":"Quadratic B = 287.956-36.906D+1.157D^2 70.5% 35.502","locator":"Table 4, Quadratic row"},{"field":"fit.n_trees","quote":"A total of 14 trees were felled to serve as measurement samples: 8 for model development and 6 for model validation.","locator":"Results and Discussion, p. 908"},{"field":"fit.r2","quote":"70.5%","locator":"Table 4, Quadratic row"}],"check":[{"inputs":{"D":12},"expected":11.692,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":20},"expected":12.636,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":26},"expected":110.53,"origin":"computed","note":"computed from the published form (coefficients as printed)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Stand origin is not stated in the paper; classified natural from its reference to natural forest stands. Fitted on 8 of the 14 felled trees (the other 6 were held out for validation); the paper prints no DBH range for the fitting trees. The polynomial goes negative between about D = 14 and 18 cm, inside the sampled size range; the paper's Conclusion prints the linear coefficient as 3.906D, while Tables 4 and 12 print 36.906D (table value used)."}