{"id":"magalhaes-2015-root-system-rcd","source":{"id":"magalhaes-2015","citation":"Magalhães, T.M. (2015). Allometric equations for estimating belowground biomass of Androstachys johnsonii Prain. Carbon Balance and Management, 10, 16.","title":"Allometric equations for estimating belowground biomass of Androstachys johnsonii Prain","authors":["Magalhães, T.M."],"year":2015,"venue":"Carbon Balance and Management","doi":"10.1186/s13021-015-0027-4","url":"https://doi.org/10.1186/s13021-015-0027-4","read_url":"https://cbmjournal.biomedcentral.com/track/pdf/10.1186/s13021-015-0027-4","access":"open","license":"CC BY 4.0","checked_at":"2026-11-02","status":"current"},"name":"Root system dry biomass from root collar diameter (Table 4, form 7)","output":{"quantity":"bgb"},"expression":"0.023 * DRC^2.4519","published":{"expression":"0.023 * RCD^2.4519","units":{"RCD":"cm"},"variables":{"RCD":"DRC"},"output_unit":"kg"},"taxon":{"level":"species","name":"Androstachys johnsonii","family":"Picrodendraceae","group":"broadleaf"},"region":{"scope":"regional","countries":["MZ"],"place":"Mabote, Funhalouro, Panda, Mandlakaze and Chibuto districts, Inhambane and Gaza provinces","biomes":["tropical","dryland"]},"stand":"natural","fit":{"n_trees":93,"r2":0.9979,"method":"Weighted nonlinear least squares (nls, Gauss-Newton); r2 is the adjusted R² in Table 5; CVr = 28.879%"},"evidence":[{"field":"expression","quote":"Root system 4 1/0.00007 × RCD4.2484 0.0230 (±0.0042)*** 2.4519 (±0.0608)***","locator":"Table 4, Root system rows, and Eq. (7; Ŷ = b0 × RCD^b1)"},{"field":"fit.n_trees","quote":"93 trees (DBH range 5–32 cm; TH range 5.69–16 m)","locator":"Methods, Data acquisition"},{"field":"fit.r2","quote":"Root system 4 99.79 28.8790","locator":"Table 5, Root system"},{"field":"output","quote":"The dry weight of the root system was obtained by summing the dry weights of taproot and lateral roots (fine and coarse ones).","locator":"Methods, Data acquisition"}],"check":[{"inputs":{"DRC":10},"expected":6.5107,"origin":"computed","note":"hand-computed from the Table 4 coefficients"},{"inputs":{"DRC":20},"expected":35.622,"origin":"computed","note":"hand-computed from the Table 4 coefficients"},{"inputs":{"DRC":30},"expected":96.268,"origin":"computed","note":"hand-computed from the Table 4 coefficients"}],"verification":"original_read","checked_at":"2026-11-02","notes":"For felled trees where only stump dimensions are available. RCD is the root collar diameter (mapped to DRC); the paper does not define its measurement height in the text read. Fit range quoted is the DBH range of the sample (RCD range not stated), so dbh_min/max are dropped for this equation. Weight function 1/(0.00007 × RCD^4.2484). Root system = taproot (including root collar) + lateral roots, excavated to full depth, fine roots included, dry mass at 105 C; stump above 20 cm is not part of it. Independent (not WNSUR additive) model, which the author recommends over the simultaneous ones. One of four independent root-system models in Table 4; all performed almost equally."}