Changes in ground‐layer plant species assemblages and successional patterns following a decade of oak regeneration restoration

Open forest restoration transitions closed‐canopy forests to a structure amenable to shade‐intolerant species such as oak and often includes thinning or prescribed burns to promote diverse species composition. We measured how oak restoration treatments influenced ground‐layer species assemblages and successional patterns in an ecologically diverse mesic hardwood forest. We tested how repeated prescribed fire, midstory herbicide applications, and the combination of shelterwood overstory harvest and prescribed fire influenced species diversity and turnover, and if species showed affinity to particular treatments throughout time. We monitored ground‐layer species composition, abundance, and environmental variables for 9–11 years across manipulated forest stands. Species richness increased after roughly a decade following all treatments (+12 species following repeated fire, +9 species following shelterwood/fire, and +6 species following midstory herbicide) relative to controls (no increase), without substantial species turnover. The paired shelterwood/fire treatment increased light availability to the ground‐layer 10‐fold the year following overstory harvest, altering environmental parameters, species diversity, and successional patterns more than the individual midstory herbicide or repeated fire treatments. This treatment also increased Rubus spp. dominance, which persisted as a recalcitrant layer after 9 years. Transitioning closed‐canopy forests for oak restoration simultaneously influences the diversity of the forest ecosystem, primarily following the combination of thinning and repeated fire treatments.