Summary• Nitrogen transfer among plants in a California oak woodland was examined in a pulse-labeling study using 15 N. The study was designed to examine N movement among plants that were mycorrhizal with ectomycorrhizas (EM), arbuscular mycorrhizas (AM), or both.• Isotopically enriched N (K 15 NO 3 -) was applied to gray pine ( Pinus sabiniana ) foliage (donor) and traced to neighboring gray pine, blue oak ( Quercus douglasii ), buckbrush ( Ceanothus cuneatus ) and herbaceous annuals ( Cynosurus echinatus , Torilis arvensis and Trifolium hirtum ).• After 2 wk, needles of 15 N-treated pines and foliage from nearby annuals were similarly enriched, but little 15 N had appeared in nontreated (receiver) pine needles, oak leaves or buckbrush foliage. After 4 wk foliar and root samples from pine, oak, buckbrush and annuals were significantly 15 N-enriched, regardless of the type of mycorrhizal association.• The rate of transfer during the first and second 2-wk periods was similar, and suggests that 15 N could continue to be mobilized over longer times.