{"id":"khun-2008-v-dh","source":{"id":"khun-2008","citation":"Khun, K., Mizoue, N., Yoshida, S., & Murakami, T. (2008). Stem Volume Equation and Tree Growth For Rubber Trees in Cambodia. Journal of Forest Planning, 13, 335-341.","title":"Stem Volume Equation and Tree Growth For Rubber Trees in Cambodia","authors":["Khun, K.","Mizoue, N.","Yoshida, S."],"year":2008,"venue":"Journal of Forest Planning","doi":"10.20659/jfp.13.2_335","url":"https://doi.org/10.20659/jfp.13.2_335","read_url":"https://www.jstage.jst.go.jp/article/jfp/13/2/13_KJ00007911384/_pdf","access":"open","checked_at":"2026-11-02","status":"current"},"name":"Rubber (PR107) stem volume from D and H (Eq. 9, Schumacher-Hall)","output":{"quantity":"stem_volume"},"expression":"0.00018381 * D^2.23961 * H^0.15334","published":{"expression":"0.00018381 * D^2.23961 * H^0.15334","units":{"D":"cm","H":"m"},"output_unit":"m3"},"taxon":{"level":"species","name":"Hevea brasiliensis (clone PR107)","family":"Euphorbiaceae","group":"broadleaf"},"region":{"scope":"site","countries":["KH"],"place":"Krek Rubber Plantation, Kompong Cham Province","biomes":["tropical"]},"stand":"plantation","fit":{"n_trees":60,"dbh_min_cm":20,"dbh_max_cm":62,"h_min_m":16.7,"h_max_m":47,"r2":0.9245,"method":"log-log linear regression (log10) of over-bark stem volume on D (and H), 60 felled trees, ages 36-46 years"},"evidence":[{"field":"expression","quote":"log V = -3.73563 + 2.23961 log D + 0.15334 log H (R2 = 0.9245, N = 60), or V = 0.00018381 D^2.23961 H^0.15334","locator":"Eqs. 8-9, p. 338"},{"field":"fit.r2","quote":"R2 = 0.9245, N = 60","locator":"Eq. 8, p. 338"},{"field":"fit.dbh_min_cm","quote":"The range of data is 20-62cm for DBH, 16.7-47.0m for total height, and 0.25 to 3.41m³ for stem volume.","locator":"Results and Discussion, Volume Equations, p. 338"}],"check":[{"inputs":{"D":30,"H":28},"expected":0.6229,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":45,"H":32},"expected":1.5766,"origin":"computed","note":"computed from the published form (coefficients as printed)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Volume is over-bark stem volume of 60 felled PR107 trees (1 m sections, Smalian). Logs are base 10: 10^-3.6041 = 0.00024884 and 10^-3.73563 = 0.00018381 as printed. R2 is of the log-log regression. Ranges follow the text on p. 338; Table 1 (p. 337) prints per-stand minima/maxima whose overall span is DBH 26.0-62.0 cm and height 16.2-47.3 m, which does not match the text exactly."}