{"id":"kang-2016-root-quad-d","source":{"id":"kang-2016","citation":"Kang, M.S., Jang, K.S., Son, Y.M., et al. (2016). Allometric Equations and Biomass Expansion of Yellow Poplar (Liriodendron tulipifera) in Southern Korea. Journal of Korean Forest Society, 105(4), 463-471.","title":"Allometric Equations and Biomass Expansion of Yellow Poplar (Liriodendron tulipifera) in Southern Korea","authors":["Kang, M.S.","Jang, K.S.","Son, Y.M."],"year":2016,"venue":"Journal of Korean Forest Society","doi":"10.14578/jkfs.2016.105.4.463","url":"https://doi.org/10.14578/jkfs.2016.105.4.463","read_url":"http://e-journal.kfs21.or.kr/journal/view.asp?key=3493107","access":"open","license":"CC BY-NC 3.0","checked_at":"2026-11-02","status":"current"},"name":"Liriodendron tulipifera Root W = aD + bD^2 (Table 10)","output":{"quantity":"bgb"},"expression":"-1.943 * D + 0.155 * D^2","published":{"expression":"-1.943 * DBH + 0.155 * DBH^2","units":{"DBH":"cm"},"variables":{"DBH":"D"},"output_unit":"kg"},"taxon":{"level":"species","name":"Liriodendron tulipifera","family":"Magnoliaceae","group":"broadleaf"},"region":{"scope":"regional","countries":["KR"],"place":"Suwon (Gyeonggi), Jangseong and Gangjin (Jeollanam-do), South Korea","biomes":["temperate"]},"stand":"plantation","fit":{"r2":0.919,"method":"regression in SPSS 19.0"},"evidence":[{"field":"expression","quote":"Root -1.943 0.155 0.919","locator":"Table 10 (W=aD+bD^2)"}],"check":[{"inputs":{"D":15},"expected":5.73,"origin":"computed","note":"computed from the Table 10 coefficients"},{"inputs":{"D":30},"expected":81.21,"origin":"computed","note":"computed from the Table 10 coefficients"}],"verification":"original_read","checked_at":"2026-11-02","notes":"W = dry weight in kg (Table 7 in kg), D = DBH in cm. The paper prints no correction factor, so none is applied. Predicts negative biomass below about 12 cm DBH (authors' remark), so the authors prefer the power form. Only 21 of the 40 trees were excavated for roots; the paper does not state n or the DBH/height range for this equation, so they are omitted."}