PARENT SESSION
OOS 5: Restoration Effects of Fire and Thinning Treatments on Mixed-Conifer Ecosystems.
Organized by: M North and J Innes
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room E 148.

Forests, fungi, and small mammals: The impact of fire and thinning on truffle production and consumption.

Meyer, Marc^{*,1, 2}, North, Malcolm^{1, 3}, Kelt, Douglas², ¹ Sierra Nevada Research Center, Davis, CA, USA² Department of Wildlife, Fish, and Conservation Biology, Davis, CA, USA³ Department of Environmental Horticulture, Davis, CA, USA

ABSTRACT- In many western forests, prescribed burning and mechanical thinning are widely used to reduce fuels and restore stand conditions after a century of fire suppression. Few studies have examined the impact of these treatments on forest ecosystems and their key interactions, such as the mutualism between forest trees, truffle-producing ectomycorrhizal fungi, and truffle-consuming small mammals. We examined the short-term impact of prescribed burning (burned vs. unburned), mechanical thinning (light, heavy, and none), and combinations of these treatments on the production of truffles and their consumption by lodgepole chipmunks (Tamias speciosus) at Teakettle Experimental Forest, a mixed conifer and red fir forest in the southern Sierra Nevada. Truffles and chipmunk diets were sampled 1-2 years after burning and 2-3 years after thinning. Truffle frequency, biomass, and richness were significantly lower on plots that had been burned and/or thinned, as was the frequency and richness of truffles in chipmunk diets. Additionally, plots treated with both thinning and burning together had a significantly lower frequency and richness of truffles in both truffle samples and chipmunk diets than plots burned alone. These results suggest that both burning and thinning can impact the interaction between small mammals and truffles, by reducing the consumption and potentially the dispersal of ectomycorrhizal truffle spores by small mammals. Moreover, more intensive management treatments that incorporate both burning and thinning may have a greater negative impact on these beneficial interactions than less intensive management approaches (i.e., prescribed burning without thinning). These short-term results underscore the need for longer term monitoring of burning and thinning effects on this key forest interaction.

Key words: thinning, Sierra Nevada, burning, truffles