{"id":"petrova-2026-birch-br","source":{"id":"petrova-2026","citation":"Petrova, I.V., Plukha, N.I., Usoltsev, V.A., et al. (2026). Aboveground biomass and its allometric models for the main and under storeys of the forest-swamp system in the Middle Urals. Forests of Russia and economy in them, 3(98), 118–134.","title":"Aboveground biomass and its allometric models for the main and under storeys of the forest-swamp system in the Middle Urals","authors":["Petrova, I.V.","Plukha, N.I.","Usoltsev, V.A."],"year":2026,"venue":"Леса России и хозяйство в них (Forests of Russia and economy in them)","doi":"10.51318/fret.2026.98.3.012","url":"https://doi.org/10.51318/fret.2026.98.3.012","read_url":"https://usfeu.ru/media/filer_public/46/8f/468f8f54-0a39-4ff0-a7a5-0c995daa8d5b/12_petrova_i_dr_nadzemnaia_biomassa_i_ee2.pdf","access":"open","checked_at":"2026-11-01","status":"current"},"name":"Betula pendula branches biomass vs DBH (Eq. 4), forest-swamp, Middle Urals","output":{"quantity":"branch_biomass"},"expression":"exp(-4.348 + 2.3432 * ln(D))","published":{"expression":"exp(-4.348 + 2.3432 * ln(D))","units":{"D":"cm"},"output_unit":"kg"},"taxon":{"level":"species","name":"Betula pendula","family":"Betulaceae","group":"broadleaf"},"region":{"scope":"site","countries":["RU"],"place":"Forest-swamp system by Lake Isetskoe, Sverdlovsk Oblast, Middle Urals","biomes":["boreal"]},"stand":"natural","fit":{"n_trees":18,"dbh_min_cm":1.1,"dbh_max_cm":17.1,"h_min_m":2.1,"h_max_m":14.5,"rse":0.554,"method":"log-log regression (OLS on natural logs); Baskerville correction included in the intercept"},"evidence":[{"field":"expression","quote":"lnPi = a0 + a1lnD (4); lnPbr: a0 = –4,348, a1 = 2,3432","locator":"Eq. (4) and Table 4, p. 126"},{"field":"fit.n_trees","quote":"18 и 12 деревьев соответственно березы и сосны","locator":"Abstract (RU)"}],"check":[{"inputs":{"D":5},"expected":0.561713,"origin":"computed","note":"hand-computed from the published form (Table 4 coefficients)"},{"inputs":{"D":10},"expected":2.85028,"origin":"computed","note":"hand-computed from the published form (Table 4 coefficients)"},{"inputs":{"D":15},"expected":7.37063,"origin":"computed","note":"hand-computed from the published form (Table 4 coefficients)"}],"verification":"original_read","checked_at":"2026-11-01","notes":"The Baskerville log-correction is already in the printed intercept a0 (Table 4 footnote), so no separate factor. adjusted R2 reported: 0.896 (not used as r2). Pa excludes dead branches (reported separately as Pmort); the contract cannot express that exclusion. Only the 4 main fractions (stem in bark, branches, foliage, total) are added; bark and dead-branch fits omitted. 18 birch and 12 pine trees from 4 plots in one forest-swamp system."}