There is a lot of information at Field and Forest Products (www.fieldforest.net) . I know there are other suppliers but this is where we order our plugs. There are
alot of shiitake growers in our area so when we started we had a lot of
local advice...which was to cut when dormant and plug soon after. We are using some red, white and black oak, whatever is the right size and needs thinning, I don't know about any others but have found this company helpful on the phone. (our "computer" is an amazonkindle with browser capabilities but not much else...like the ability to link).
"We're all just walking each other home." -Ram Dass
"Be a lamp, or a lifeboat, or a ladder."-Rumi
"It's all one song!" -Neil Young