Concentrations of ammonium-N (a) and nitrate-N (b) in surface soil (0–10 cm depth) at different times after harvesting and slash management. Vertical bars, standard error. Note the different scales. C, control (uncut trees); S, clearcutting + slash scattering; SF, clearcutting + slash scattering + fertilization; W, clearcutting + windrowing; BB, clearcutting + broadcast burning; WB, clearcutting + windrow burning. Values indicated by the same letter in the same measurement date did not differ significantly (p < 0.05).