{"id":"xu-2015-i2-d2hwd","source":{"id":"xu-2015","citation":"Xu, Y., Zhang, J., Franklin, S. B., et al. (2015). Improving allometry models to estimate the above- and belowground biomass of subtropical forest, China. Ecosphere, 6(12), 289.","title":"Improving allometry models to estimate the above- and belowground biomass of subtropical forest, China","authors":["Xu, Y.","Zhang, J.","Franklin, S. B."],"year":2015,"venue":"Ecosphere","doi":"10.1890/es15-00198.1","url":"https://doi.org/10.1890/es15-00198.1","read_url":"https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/ES15-00198.1","access":"open","license":"CC BY 3.0","checked_at":"2026-11-02","status":"current"},"name":"Subtropical China AGB from D²H and wood density (Model I.2)","output":{"quantity":"agb"},"expression":"exp(-2.672 + 0.944 * ln(D^2 * H) + 0.615 * ln(rho))","published":{"expression":"exp(-2.672 + 0.944 * ln(D^2 * H) + 0.615 * ln(WD))","units":{"D":"cm","H":"m","WD":"g/cm3"},"variables":{"WD":"rho"},"output_unit":"kg"},"taxon":{"level":"mixed","name":"41 subtropical forest tree species (Fagus lucida, Castanea seguinii, Carpinus viminea and others)","group":"mixed"},"region":{"scope":"site","countries":["CN"],"place":"Badagongshan National Nature Reserve, Hunan province","biomes":["subtropical","montane"]},"stand":"natural","fit":{"n_trees":147,"r2":0.939,"rse":0.193,"method":"Bayesian log-log regression (MCMC)"},"evidence":[{"field":"expression","quote":"I.2  ln(AGB) = a + bln(D²H) + cln(WD)   −2.672  0.944  0.615","locator":"Table 2, model I.2"},{"field":"fit.r2","quote":"I.2  R² 0.939  RSE 0.193","locator":"Table 3, model I.2 (R2 and RSE columns)"},{"field":"fit.n_trees","quote":"we harvested and weighted dry mass of 147 trees from 41 dominant species in subtropical forest","locator":"Abstract"}],"check":[{"inputs":{"D":20,"H":14,"rho":0.57},"expected":168.9342,"origin":"computed","note":"computed from the printed coefficients"},{"inputs":{"D":40,"H":20,"rho":0.6},"expected":903.6281,"origin":"computed","note":"computed from the printed coefficients"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Log-log model fitted by Bayesian MCMC; no correction factor is stated, so none is applied. Natural log assumed from the paper's ln notation. Wood density WD is in g cm-3 (Table 2; the running text says g/m3). Whole-tree AGB includes branches, leaves and fruit."}