1. Introduction: Mycorrhizal fungi are ubiquitous plant mutualists and can form mycorrhizal networks (MNs), consisting of fungal hyphae that connect plants of the same and different species. The degree to which the MNs of adult trees facilitate or inhibit other plants, specifically seedlings, is unclear.

2. Research Objective: This study examines how the MNs associated with different species of adult trees affect mycorrhizal colonization, growth, survival, and root fungal community of Quercus rubra seedlings, an ectomycorrhizal (EM) tree species.

3. Methods: Seedlings were planted under four adult tree species: Q. rubra, Q. velutina, Acer saccharum, and Carya glabra. Two thirds of the seedlings were grown in micromesh bags. Seedlings were separated into treatment groups: no bag control (C), bagged control (BC), and disturbed (D). C and BC groups were grown undisturbed. Seedlings in the D group had their connection to the MNs consistently disrupted. Seedlings were collected at the end of the growing season. A subset of the seedlings was examined for EM colonization, and all colonized tips were collected. Collected tips had fungal DNA sequenced to determine the EM community.

4. Results: Seedling survival in the D treatment group was negatively impacted by mycorrhizal colonization, while survival in the control groups, BC and C, was unaffected. D seedlings were colonized by a different suite of EM taxa than control seedlings. Our data indicate that that MNs have a positive impact on Q. rubra seedling recruitment regardless of the species of adult tree a seedling is grown under. This work represents an important additional step in advancing our understanding of the role that mycorrhizal MNs play in how temperate forest communities assemble.