Tree mycorrhizal type mediates the strength of negative density dependence in temperate forests

1. Recent plant-soil feedback experiments suggest that arbuscular mycorrhizal (AM) tree species experience stronger conspecific negative density dependence (CNDD) than ectomycorrhizal (EM) tree species. Yet how these findings inform our understanding of natural systems is limited because the roles of local soil conditions, light environments and tree species abundances in influencing CNDD for AM and EM species are not clear.

2. Here we examined seedling and sapling survival in two temperate old-growth forests (broadleaved pine and spruce-fir forests) in Northeast China, to evaluate the effects of both conspecific and heterospecific neighbour density, as well as the soil and light environments, on the survival of AM and EM-dependent trees at early life stages.

3. While light availability increased the survival of EM seedlings, soil organic resources increased EM sapling survival in the spruce-fir plot. AM seedlings suffered stronger CNDD than did EM seedlings in both plots. In the ...