Expanding on the notion that the establishment of trees in contaminated soils is enhanced by use of ectomycorrhizal (EM) fungi, NASA researchers developed technology for EM-mediated remediation of phenolic-based contaminated soils.

EM fungi impart resistance to soil extremes such as high temperature, high acidity and heavy metal contamination. This process for soil remediation, which is available for licensing, uses specific plant/fungal combinations that are adapted to conditions created by phenolic application to soils, and abilities of EM fungi to oxidize these compounds.

The approach exploits the ability of native fungi to upregulate enzyme genes in response to changes in host physiological condition and enhance natural phenolic oxidation in soils by up to five-fold. Fungi in the genera Russula and Piloderma react with positive growth responses to phenolic-based soil contamination. The activities of enzymes that oxidize these compounds increase in activity by five-fold when the host tree is partially defoliated, which in turn imparts an increase in phenolic oxidation in soils by a similar amount. Defoliation is done by pine needle removal, where 50 percent of the needles are removed. This process is performed each year on new growth to maintain defoliation.