{"id":"cihak-2018-stem-d-hd","source":{"id":"cihak-2018","citation":"Čihák, T., & Vejpustková, M. (2018). Parameterisation of allometric equations for quantifying aboveground biomass of Norway spruce (Picea abies (L.) H. Karst.) in the Czech Republic. Journal of Forest Science, 64(3), 108–117.","title":"Parameterisation of allometric equations for quantifying aboveground biomass of Norway spruce (Picea abies (L.) H. Karst.) in the Czech Republic","authors":["Čihák, T.","Vejpustková, M."],"year":2018,"venue":"Journal of Forest Science","doi":"10.17221/61/2017-jfs","url":"https://doi.org/10.17221/61/2017-jfs","read_url":"https://www.agriculturejournals.cz/publicFiles/61_2017-JFS.pdf","access":"open","checked_at":"2026-11-02","status":"current"},"name":"Norway spruce, Czech Republic: Stem biomass from D and H/D (Table 2)","output":{"quantity":"stem_biomass"},"expression":"exp(-3.62155 + 2.84648 * ln(D) + 1.0886 * ln(H/D)) * 1.002","published":{"expression":"exp(-3.62155 + 2.84648 * ln(D) + 1.0886 * ln(H/D)) * 1.002","units":{"D":"cm","H":"m"},"output_unit":"kg"},"taxon":{"level":"species","name":"Picea abies","family":"Pinaceae","group":"conifer"},"region":{"scope":"national","countries":["CZ"],"place":"25 stands on 15 sites, Czech Republic (acidic and nutrient-medium sites)","biomes":["temperate"]},"stand":"mixed","fit":{"n_trees":139,"r2":0.96,"cf":1.002,"method":"log-log linear regression with Marklund (1987) back-transformation correction factor"},"evidence":[{"field":"expression","quote":"ST = exp(b0 + b1ln(D) + b2ln(H/D))λ; b0 = -3.62155, b1 = 2.84648, b2 = 1.0886, λ = 1.002","locator":"Table 2 and Eq. 2, p. 113 and p. 110"},{"field":"fit.n_trees","quote":"an extensive data set of 139 spruce trees collected in 25 stands on 15 sites","locator":"Abstract"}],"check":[{"inputs":{"D":10,"H":10},"expected":18.8161,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":25,"H":22},"expected":222.2392,"origin":"computed","note":"computed from the published form (coefficients as printed)"},{"inputs":{"D":45,"H":30},"expected":875.3706,"origin":"computed","note":"computed from the published form (coefficients as printed)"}],"verification":"original_read","checked_at":"2026-11-02","notes":"Coefficients, R2 and lambda as printed in Table 2 (lambda per Marklund 1987, Eq. 3, already multiplied in). H/D is slenderness ratio, tree height (m) over DBH (cm). Stem biomass excludes the stump. Not recommended for trees with D < 7 cm. Table 2 also gives models with site index (SI) or tree age (A) and crown biomass models, not added here (no canonical variable for SI or A; crown has no output quantity)."}