Our ongoing research project with East Bay Municipal Utility District (EBMUD), investigating the use of native fungi to control growth of invasive trees.

In late 2020 we began a research project with EBMUD to investigate the use of native fungi as a means to control regrowth of felled Blue Gum Eucalyptus trees. Blue Gum trees were imported from Australia in the late 1800’s, and widely planted in California. They have become naturalized and in many cases invasive in the California landscape. Blue gum are well adapted to the regular fires in their native Australian habitat, storing large amounts of energy underground, so that they can be the first thing to resprout after fire removes other vegetation from the landscape.

On EBMUD property there are several stands of Blue Gum that pose both windfall and fire hazards. The stands must be periodically thinned, leaving re-sprouting stumps that must be regularly “sprout-busted,” sometimes for up to 10 years. The costs of this maintenance work can be substantial over the long-run.

Conventional treatment of resprouting stumps involves the use of herbicides like Triclopyr and Imazapyr. There are strict regulations against the use of chemical herbicide in the watersheds that EBMUD manages, so the strategy has been for maintenance teams to manually remove the re-growth once per year until the stumps stop producing new sprouts.

Bay Area Applied Mycology has worked with EBMUD in the past to inoculate blue gum trees with Trametes versicolor, and while the results were promising, the experiment’s methods and data-collection were not highly rigorous. In our current study, we are attempting to generate high-quality data to establish whether inoculating Blue Gum with native fungi significantly reduces stump-resprouting over time.

Currently we have two research plots along Grizzly Peak Boulevard, in the Berkeley Hills. We have inoculated the two treatment groups with a locally harvested culture of Omphalotus olivascens, otherwise known as “Western Jack o’ Lantern” for the large, orange, bioluminescent mushrooms the fungi produces when it fruits.

Over the course of our 3-year study, we are visiting the plots at 6-month intervals, removing sprouts from both experimental and control populations, and measuring the weight of sprouts that are removed. We are looking for any significant differences in the weight of material removed, and the time until regrowth ceases.

Our plan is to eventually expand our research to investigate the efficacy of other fungal species, and for control of other invasive plants.

We are looking for volunteers to help with our current and future efforts.