Vast Underground Network of Fungi Detected from Space
Tree-mycorrhizal associations detected remotely from canopy spectral properties.
Researchers used satellite measurements of forest canopies to detect belowground fungal associations with trees across landscapes, testing the findings with 130,000 trees throughout the United States.
Nearly all tree species associate with only one of two types of mycorrhizal fungi—arbuscular mycorrhizal (AM) fungi or ectomycorrhizal (ECM) fungi. AM- and ECM-dominated forests have distinct nutrient economies, so detection and mapping of these fungi can provide key insights into fundamental ecosystem properties.
Hidden belowground is a vast network of fungi that operates in a complex economy within forests, scavenging for nutrients and trading them to trees for carbon sugars. Researchers in a Department of Energy-supported study figured out how to detect this underground network from space. Understanding how different forests get their nutrients is critical to predicting how forests may grow—or be growth-stunted due to lack of nutrients—into the future. The type of mycorrhizal fungi is a key piece of that puzzle in determining how forests will respond to future changes in climate, carbon dioxide, water, and temperature. Scientists have known for many years which tree species associate with which fungi, but mapping every single tree species across large scales such as landscapes or continents has not been possible. The researchers used Landsat satellite measurements of forest canopies to detect mycorrhizal associations. They gathered data from 130,000 trees throughout the United States to test their approach, finding that they could predict 77% of the differences in mycorrhizal associations known on the ground from satellite observations alone.
University of California, Los Angeles; Jet Propulsion Laboratory
Funding for the remote sensing analysis was provided by the U.S. Department of Energy, Office of Biological and Environmental Research, Terrestrial Ecosystem Science program; National Science Foundation Ecosystem Science Program; and Indiana University.
Fisher, J. B., S. Sweeney, E. R. Brzostek, T. P. Evans, D. J. Johnson, J. A. Myers, N. A. Bourg, A. T. Wolf, R. W. Howe, and R. P. Phillips. 2016. “Tree-Mycorrhizal Associations Detected Remotely from Canopy Spectral Properties,” Global Change Biology 22(7), 2596-2607. DOI: 10.1111/gcb.13264.