Understory vegetation response to alternative silvicultural systems in coastal British Columbia montane forests

•Species richness and diversity peaked 15 years after forest harvesting.•A shelterwood increased Vaccinium shrub cover more than other systems.•Silvicultural system had a greater effect on 26-year shrub cover than early control.•Forest floor bryophyte cover remains one-third or less than pre-harvest cover.•Retention patches (0.8–0.9 ha) retained late-seral species with few edge effects.