{"id":"du-2026-fir-total","source":{"id":"du-2026","citation":"Du, Z., Liu, Z., Wang, J., Zou, Z., He, W., Zeng, W., Meng, J., & Chen, Z. (2026). Development of Compatible Biomass Models for Chinese Fir, Poplar, and Oak in Hunan Province. Forests, 17(7), 770.","title":"Development of Compatible Biomass Models for Chinese Fir, Poplar, and Oak in Hunan Province","authors":["Du, Z.","Liu, Z.","Wang, J."],"year":2026,"venue":"Forests","doi":"10.3390/f17070770","url":"https://doi.org/10.3390/f17070770","read_url":"https://www.mdpi.com/1999-4907/17/7/770/pdf?version=1782822414","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current"},"name":"Chinese fir total tree biomass (compatible total-biomass system)","output":{"quantity":"total_biomass"},"expression":"0.065662 * D^1.750420 * H^0.780381 + 0.024760 * (D^2 * H)^0.774387","published":{"expression":"0.065662 * D^1.750420 * H^0.780381 + 0.024760 * (D^2 * H)^0.774387","units":{"D":"cm","H":"m"},"output_unit":"kg"},"taxon":{"level":"species","name":"Cunninghamia lanceolata","family":"Cupressaceae","group":"conifer"},"region":{"scope":"regional","countries":["CN"],"place":"Hunan Province (14 prefecture-level cities and autonomous prefectures)","biomes":["subtropical"]},"stand":"mixed","fit":{"n_trees":154,"dbh_min_cm":2.2,"dbh_max_cm":35.3,"h_min_m":2.5,"h_max_m":25.6,"r2":0.9208,"method":"weighted nonlinear least squares"},"evidence":[{"field":"fit.n_trees","quote":"The sample comprised 154 Chinese fir, 150 poplar, and 157 oak trees.","locator":"Section 2.2"},{"field":"fit.dbh_min_cm","quote":"DBH (cm) 2.2 35.3 19.88 7.77","locator":"Table 1, Chinese fir"},{"field":"fit.h_min_m","quote":"Tree height (m) 2.5 25.6 14.25 5.38","locator":"Table 1, Chinese fir"},{"field":"expression","quote":"Btotal = 0.065662D 1.750420 H 0.780381 + 0.024760 (D 2 H) 0.774387 (29)","locator":"Table 8, Eq. 29-31"},{"field":"expression","quote":"(20) 0.065662 1.750420 0.780381 0.024760 0.774387 10.77 7.19 44.54 6.16","locator":"Table 8 (parameters)"},{"field":"fit.r2","quote":"R2 0.9208 (total biomass model, evaluation table)","locator":"Table 11"}],"check":[{"inputs":{"D":10,"H":9},"expected":25.333,"origin":"computed","note":"hand-computed from the published form"},{"inputs":{"D":30,"H":20},"expected":310.8,"origin":"computed","note":"hand-computed from the published form"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Final total-biomass model (aboveground + root). Compatible total-biomass system (aboveground fitted independently, total and root fitted jointly by simultaneous estimation; weighted nonlinear least squares). Total = aboveground + root. The paper lists the sample as stratified random felled trees across eight diameter classes (4-32 cm) from 2022-2023; the reported minimum and maximum DBH and height are for all sampled trees of the species (Table 1). Root biomass was measured on a subset only (whole-root excavation: root collar, coarse roots, fine roots), so root and total fit ranges are not given beyond the full sample. No back-transform factor (nonlinear fit). The paper also gives aboveground-component (stem, crown, wood, bark, branch, foliage) systems (Tables 17-39), not added here."}