# Commercial stem volume from DBH, Couratari (species-specific, Table 2) Stem volume equation for Couratari, Brazil, from Santos et al. 2020. 2,974 trees, DBH from 50 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it. ## Equation As printed in Santos et al. 2020 (Table 2, SSEs rows): > Couratari sp. vc = exp(-5.53516 + 1.71104ln(DBH)) 0.48 2.635 31.0 Cite: https://treeallometry.org/equations/santos-2020-couratari/#equation In this library's units, ready to compute (stem volume in m³): ``` Stem volume = exp(-5.53516 + 1.71104 * ln(D)) ``` Inputs: D = Diameter at breast height (1.3 m) (cm). The source's own form: exp(-5.53516 + 1.71104 * ln(DBH)), with DBH in cm; output in m3. Cite: https://treeallometry.org/equations/santos-2020-couratari/#canonical ## What it covers - Output: Stem volume, m³ - Taxon: Couratari (genus), family Lecythidaceae; broadleaf - Where: Tapajós National Forest, Pará (community forest management concession), eastern Brazilian Amazon. Cite: https://treeallometry.org/equations/santos-2020-couratari/#where - Biomes: tropical - Stand: natural - Trees measured: 2,974. Cite: https://treeallometry.org/equations/santos-2020-couratari/#n_trees - DBH range: from 50 cm. Cite: https://treeallometry.org/equations/santos-2020-couratari/#dbh - R²: 0.48. Cite: https://treeallometry.org/equations/santos-2020-couratari/#r2 - Method: Model 2 (Husch) fitted by least squares on ln(vc); r2 is the adjusted R² recalculated in arithmetic units; Syx = 2.635 m3 (31.0%). Cite: https://treeallometry.org/equations/santos-2020-couratari/#method - Verification: read in the original source - Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/santos-2020-couratari/#checked_at A missing fit statistic is one the source doesn't state, or that we haven't recorded; it is never estimated. Outside the stated DBH range or region, the equation is an extrapolation. ## Source Santos, M.F. dos, Figueiredo Filho, A., Gama, J.R.V., Retslaff, F.A. de S., Costa, D.L. da (2020). Species-specific equations: greater precision in commercial volume estimation in managed forests in the Amazon. CERNE, 26(3), 315-330. - DOI: https://doi.org/10.1590/01047760202026032741 - Access: open access - Copy we read: https://www.scielo.br/j/cerne/a/wVP9VN9KTRZwBYfg8yngfPL/?lang=en&format=pdf - Every equation from this source: https://treeallometry.org/sources/santos-2020/ - Cite: https://treeallometry.org/equations/santos-2020-couratari/#source ## The facts, in the source's words **Equation** (Table 2, SSEs rows): > Couratari sp. vc = exp(-5.53516 + 1.71104ln(DBH)) 0.48 2.635 31.0 Cite: https://treeallometry.org/equations/santos-2020-couratari/#equation **Trees measured** (Table 1 (columns: adjustment, validation)): > Couratari sp. Tauarí 2,974 330 Cite: https://treeallometry.org/equations/santos-2020-couratari/#quote-fit-n-trees **Smallest DBH** (Material and Methods, Data collection): > 29,119 trees (50.0 cm ≤ DBH ≤ 175.0 cm) of 43 commercial species Cite: https://treeallometry.org/equations/santos-2020-couratari/#quote-fit-dbh-min-cm **Output** (Material and Methods, Data collection): > composed the commercial volume (vc) of the stem Cite: https://treeallometry.org/equations/santos-2020-couratari/#quote-output **Our note:** Species-specific equation (Couratari sp., Tauarí). vc is the commercial volume of the stem (sum of Smalian log volumes, hollows discounted), not total tree volume. No back-transformation correction factor is stated, so none is applied. n_trees is the adjustment (fitting) set; DBH range is that of the whole dataset (all species), not stated per species. Ten percent of trees were held out for validation. 8 of the 36+1 species equations in Table 2 were added (the ten most important commercial species by harvested volume plus H. petraeum); the generic FMA equation was rejected by the authors' own paired t-test. Couratari sp. in the paper (species not identified); genus-level taxon. ## Checks this equation passes On every build, the library's form and the source's own form (in its units) must both give these values within 1%. | Inputs | Expected | We get | From | | --- | --- | --- | --- | | D = 60 | 4.35 | 4.35 | Computed from the printed form: hand-computed from the Table 2 coefficients | | D = 90 | 8.71 | 8.71 | Computed from the printed form: hand-computed from the Table 2 coefficients | | D = 130 | 16.3 | 16.3 | Computed from the printed form: hand-computed from the Table 2 coefficients | Cite: https://treeallometry.org/equations/santos-2020-couratari/#checks ## How to cite Cite the source for the equation: Santos, M.F. dos, Figueiredo Filho, A., Gama, J.R.V., Retslaff, F.A. de S., Costa, D.L. da (2020). Species-specific equations: greater precision in commercial volume estimation in managed forests in the Amazon. CERNE, 26(3), 315-330. https://doi.org/10.1590/01047760202026032741 Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Commercial stem volume from DBH, Couratari (species-specific, Table 2)", checked 2026-11-02, https://treeallometry.org/equations/santos-2020-couratari/. Data CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Quotes are the authors' words. Data for this equation: https://treeallometry.org/data/equations/santos-2020-couratari.json Report a problem: email info@restorationscope.com with the equation id (santos-2020-couratari) and where the right value appears.