Kai published a paper in Journal of Ecology on mycorrhizal-tree associations across the eastern US.
Mycorrhizal fungi provide soil nutrients and receive carbon resources from their host plants, with arbuscular and ectomycorrhizal fungi forming the two most common mycorrhizal associations with forest trees. Continental-scale distribution of tree-mycorrhizal associations in relation to soil carbon and nitrogen suggests distinct signatures of mycorrhizal associations on soil nitrogen with broader impacts on soil and ecosystem properties.
Zhu K, McCormack ML, Lankau RA, Egan JF, Wurzburger N (2018). Association of ectomycorrhizal trees with high carbon-to-nitrogen ratio soils across temperate forests is driven by smaller nitrogen not larger carbon stocks. Journal of Ecology, 106, 524-535. [link]