Outcomes of commercial and forest soil inoculation on tree growth and mycorrhizal associations in a peri‐urban forest restoration experiment

Abstract Introduction Soil fungi affect tree nutrition and growth. Land development for industry, residency, and recreation may alter soil fungal communities in ways that persist beyond restoration efforts. Objectives We evaluate the effect of commercial and forest soil mycorrhizal inoculation on soil fungal communities and forest restoration outcomes as indicated by tree survival and growth. Methods We initiated a restoration experiment in 2016 by adding commercial mycorrhizal inoculum and local forest soil inoculum to tree plantings at a former golf course. In the current study, we assessed how these additions influenced growth and survival of Liriodendron tulipifera , Quercus rubra , and Prunus serotina 5 years after planting. We used high‐throughput sequencing to assess how inoculation impacted fungal communities in L. tulipifera and P. serotina soils. Results Variation in soil texture throughout the site influenced tree growth and mortality. Forest soil inoculation suppressed tree growth, but only in clay loams. The effect of forest soil differed over the project duration and depending on inoculum source location across the donor forest. Tree mortality was affected by soil texture and tree provenance, but not inoculation. Fungal composition was influenced by inoculation treatment and interacted with tree species and soil texture. Conclusions Environmental contexts and species interactions may impact the effect of forest soil inoculation on restoration outcomes.