Human Impact on Root Fungus Association of Trees

Dominant tree mycorrhizal associations shift in response to anthropogenic impacts.

The Science

Researchers used forest inventory data from the U.S. Department of Agriculture to create the first comprehensive distribution map of root fungus association of more than three million trees in the continental United States. Additionally, researchers used soil carbon and nitrogen stock data to determine soil organic material relationships to fungal type and broader human-induced changes to root-fungus association across the eastern United States and global impacts.

The Impact

Tree root fungal association has a significant effect on local soil ecosystems and carbon and nitrogen cycling. This paper provides a better understanding of the effects of human intervention and climate change on root fungus type dominance and identifies shifting patterns associated with the effects. These findings are critical for improving ecosystem models to predict forest ecosystem processes and functions in global climate change.


Research found that most regions in the eastern United States are shifting to one primary plant-fungal association (arbuscular mycorrhizal; AM), and away from the other (ectomycorrhizal; EM). These shifts include a higher dominance of AM saplings than adult trees in 7 of 11 ecoregions, meaning that this trend is going to continue and potentially escalate in the future. Further analysis shows that of all the human-induced global changes, nitrogen deposition, fire frequency, and climate change are driving factors for the shift in mycorrhizal association.

Principal Investigator

Joshua B. Fisher

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science


DOE BER Environmental System Science (formerly Terrestrial Ecosystem Science) program and the NSF Ecosystem Science program.


Jo, I., et al. "Shifts in Dominant Tree-Mycorrhizal Associations in Response to Anthropogenic Impacts." Science Advances 5 (4), eaav6358  (2019).