Morels appear in patches after wildfires

Figure 1. Location of sampling plots in Yosemite National Park

Figure 1. Location of sampling plots in Yosemite National Park.

As a Michigander, spring morel (Morchella) forages are a highly anticipated time of the year for this tasty fungus. Anecdotally, many foragers will consistently find this mushroom in great abundance one year after a wildfire. To document whether this common knowledge is correct, scientists documented the abundance and spatial variance of morels across a research site in the Sierra Nevada, one-year post burn. The study site was in Yosemite National Park during 2014, surveying 1,119-3.14 m2 plots over 2,240 m of transects (Figure 1). The researchers found morel fruiting bodies in 17.8% of plots. When estimated, this indicates an average of 1693 morels per ha. When spatially analyzed up to 9 m, an autocorrelation was discovered up to 7 m, but was strongest below 3 m, indicating a patchiness in Yosemite National Park. Therefore, it was recommended to foragers to search up to 7 m near a discovered morel.

However, the question remained as to the causation for patchiness in morel mushrooms after a fire. The authors created a conceptual model based up the following hypotheses to address this question: 1) Pre-fire morel mycelial colonies are distributed in small spatial scales, 2) The pre-fire vegetation is also spatially heterogeneous at small scales, 3) The fire may vary in intensity and behavior, creating diverse post-fire biogeochemistry, 4) Post-fire environmental conditions may vary and alter fruiting season production, and 5) All aforementioned conditions need to align to create a productive morel patch.

A final conclusion from this study addresses the concerns from over harvesting if governmental regulation on collections were lifted. Authors state at least 4 L per person per day of morels could be harvested the first year post-fire and not harm the future production. This would be an increase from the current 1 pint per person per day.

University of Washington. (2016, October 11). Morel mushrooms pop up, cluster together after wildfires. ScienceDaily. Retrieved November 9, 2016 from

Larson AJ, Cansler CA, Cowder SG, Hiebert S, Furniss TJ, Swanson ME, Lutz JA (2016) Post-fire morel (Morchella) mushrooms abundance, spatial structure, and harvest sustainability. Forest Ecology and Management. 377:16-25. 


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