they like oak that's for sure. I've got some small ones growing here but I'm just using grains (there isn't really hardwood available down here).
learned something interesting about shiitake recently - they are hyper-accumulators of radiation. I'm writing an article on this now for the site, but the basic idea is - quarantine a contaminated area, cut down a bunch of trees and inoculate with mushrooms. Let them grow and soak up the radiation, and then harvest them wearing hazmat suits and safely pick and dispose of the contaminated shrooms. Rinse and repeat =)
- Grow Mushrooms at Home