{"id":"martinez-dominguez-2020-stem","source":{"id":"martinez-dominguez-2020","citation":"Martínez-Domínguez, A., Ruiz-Aquino, F., Santiago-García, W., et al. (2020). Allometric equations to estimate aboveground and belowground biomass of Pinus patula Schiede ex Schltdl. & Cham. Forest Science and Technology, 16(3), 161-170.","title":"Allometric equations to estimate aboveground and belowground biomass of Pinus patula Schiede ex Schltdl. & Cham.","authors":["Martínez-Domínguez, A.","Ruiz-Aquino, F.","Santiago-García, W."],"year":2020,"venue":"Forest Science and Technology","doi":"10.1080/21580103.2020.1801526","url":"https://doi.org/10.1080/21580103.2020.1801526","read_url":"https://www.tandfonline.com/doi/full/10.1080/21580103.2020.1801526","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current"},"name":"Pinus patula Stem biomass from D and H (Table 4)","output":{"quantity":"stem_biomass"},"expression":"exp(-5.0347 + 1.7423 * ln(D * H))","published":{"expression":"exp(-5.0347 + 1.7423 * ln(D * TH))","units":{"D":"cm","TH":"m"},"variables":{"TH":"H"},"output_unit":"kg"},"taxon":{"level":"species","name":"Pinus patula","family":"Pinaceae","group":"conifer"},"region":{"scope":"site","countries":["MX"],"place":"Ixtlán de Juárez, Sierra Norte, Oaxaca (pine-oak forest)","biomes":["temperate","montane"]},"stand":"natural","fit":{"n_trees":25,"dbh_min_cm":3.5,"dbh_max_cm":25.7,"h_min_m":4.32,"h_max_m":20.18,"r2":0.9848,"method":"nonlinear regression (SAS PROC MODEL), exponential form"},"evidence":[{"field":"expression","quote":"y = e(−β0 + β1 ln (D × TH))","locator":"Section 3.1 (Model 1, Table 1)"},{"field":"expression","quote":"β0 5.0347, β1 1.7423, R2 0.9848","locator":"Table 4, Stem row, p. 165"},{"field":"fit.n_trees","quote":"a destructive analysis was made of 25 trees distributed in five diameter classes","locator":"Abstract"},{"field":"fit.dbh_min_cm","quote":"diameter at breast height (D) that varied from 3.5 cm to 25.7 cm, with a total height (TH) fluctuating from 4.32 m to 20.18 m","locator":"Section 3.1"}],"check":[{"inputs":{"D":8,"H":7},"expected":7.2331,"origin":"computed","note":"computed from the published form"},{"inputs":{"D":13,"H":12},"expected":43.1061,"origin":"computed","note":"computed from the published form"},{"inputs":{"D":22,"H":18},"expected":218.4851,"origin":"computed","note":"computed from the published form"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Printed form y = e^(−β0 + β1 ln(D × TH)); the tabulated β0 is positive and enters with a minus sign, as printed. Units are D in cm, TH in m, biomass in kg dry weight (Figure 3). No correction factor stated. Parameters read from Table 4 of the journal PDF (p. 165); the HTML version offers no CSV for Table 4. The paper also fits an additive simultaneous system (Table 6) with slightly different parameters; not added. The foliage model (Table 4: ϖ0 8.1986, ϖ1 1.6628, R2 0.9762) is not added here; the printed additive formula in Section 3.3 shows the foliage intercept without the minus sign, but Figure 3(d) (p. 166) prints the fitted foliage curve as y = e^(−8.198579+(1.66277 ln(D x TH))), n=25, so the sign is a typesetting slip and the model could be added as exp(−8.1986 + 1.6628 ln(D × TH)). Authors recommend use for 5 to 25 cm DBH."}