Logging-debris and vegetation-control treatments influence competitive relationships to limit 15-year productivity of coast Douglas-fir in western Washington and Oregon

•Early post-harvest increases in soil C and N were maintained over 15 years.•With annual vegetation control, stand productivity varied little among debris treatments.•On glacial outwash soils Scotch broom continued to limit Douglas-fir productivity.•In dispersed debris, native shrubs limited Scotch broom recovery after herbicides.•Douglas-fir survival was 16% greater near (≤1 m) debris piles on glacial outwash.