Fine root morphology in plots dominated by trees that associate with arbuscular mycorrhizal or ectomycorrhizal fungi in the N fertilized and reference watershed at the Bear Brook Watershed in Maine, USA during the final year of N fertilization (2016) and during the year after N fertilization ceased (2017).

Our objective was to detect possible differences in N fertilization responses of fine root morphology in plots dominated by trees that associate with arbuscular mycorrhizal fungi (AM) or ectomycorrhizal fungi (ECM). To do this, we sampled fine roots in a plot network of 6 AM and 6 ECM dominated (>65% diameter at breast height) 10 x 10 m plots in the lower elevation hardwood zone of both the reference and N fertilized watersheds (N=24 plots) at Bear Brook Watershed, in Maine USA during final year of N fertilization at Bear Brook in 2016 and during the year after N fertilization ceased in 2017.