{"id":"giri-2019-duabanga-grandiflora-gt50-d2","source":{"id":"giri-2019","citation":"Giri, K., Pandey, R., Jayaraj, R.S.C., Nainamalai, R., Ashutosh, S. (2019). Regression equations for estimating tree volume and biomass of important timber species in Meghalaya, India. Current Science, 116(1), 75-81.","title":"Regression equations for estimating tree volume and biomass of important timber species in Meghalaya, India","authors":["Giri, K.","Pandey, R.","Jayaraj, R.S.C."],"year":2019,"venue":"Current Science","doi":"10.18520/cs/v116/i1/75-81","url":"https://doi.org/10.18520/cs/v116/i1/75-81","access":"open","checked_at":"2026-11-02","status":"current"},"name":"D. grandiflora stem volume from DBH, >50 cm (Table 6)","output":{"quantity":"stem_volume"},"expression":"7.889 * (D/100)^2","published":{"expression":"7.889 * d^2","units":{"d":"m"},"variables":{"d":"D"},"output_unit":"m3"},"taxon":{"level":"species","name":"Duabanga grandiflora","family":"Lythraceae","group":"broadleaf"},"region":{"scope":"regional","countries":["IN"],"place":"Meghalaya, NE India (Garo, Khasi, Jaintia Hills and Ri-Bhoi districts)","biomes":["tropical","subtropical"]},"stand":"natural","fit":{"n_trees":25,"dbh_min_cm":50,"method":"Linear regression through the origin (SPSS), non-destructive frustum volumes (Newton's formula)"},"evidence":[{"field":"expression","quote":"V = 7.889*d2","locator":"Table 6, Diameter class >50 cm"},{"field":"published.units","quote":"all the parameters were converted into metres, and volume was calculated in cubic metres","locator":"Statistical analysis (Methods)"},{"field":"fit.n_trees","quote":"n = 75, 25 trees for each diameter class","locator":"Table 1 footnote"},{"field":"fit.dbh_min_cm","quote":"All the trees were divided into three diameter classes according to their DBH, viz. 10–30, 31–50 and >50 cm","locator":"Statistical analysis (Methods)"}],"check":[{"inputs":{"D":60},"expected":2.84004,"origin":"computed","note":"computed from the Table 6 coefficient"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Class-specific model: use only for trees in the stated DBH class. Non-destructive: volumes of standing trees were summed from laser-rangefinder frustum measurements (stem volume), not felled. The paper states d and h in metres, so published units use m; canonical form divides D (cm) by 100. Adj. R² and SE are printed per class but not stored (adj. R² is not R²). The class bounds are the sampling classes; the paper gives no measured DBH range. The paper also gives biomass = stem volume x wood specific gravity (not a fitted model, not added)."}