I have used the plug method on green freshly cut logs. I've only had one single shiitake mushroom so far. My neighbor has logs and harvests shiitake mushrooms regularly. Visit
http://www.redbayfarm.com/Shiitake.html to see how I did the log plugging.
Recently I have been combining mushroom inoculation with firewood cutting. I ordered canola oil infused with oyster mushroom spores. As per directions I diluted this oil with another 2.5 gallons of canola oil.
As you know a chain saw chain requires lubrication. The canola oil with the oyster mushroom spores is spread during the cutting of the firewood. Firewood which is stacked to dry does not retain enough moisture to allow the growth of the mushrooms.
However, stumps continue to absorb moisture through the root system which does provide moisture necessary for the mushrooms to grow. I am combining coppicing and oyster mushroom growing...oyster mushrooms only live on dead wood whereas other mushrooms attack live trees. So, I hope to add a bit of food production to my forest operations. Additionally, the oyster mushrooms should help to more quickly decompose brush piles left in the woods. In a few months I should be able to harvest some oyster mushrooms for dinner.
I also ordered some sawdust medium with shiitake mushroom spawn growing in it. For this I simply spread the sawdust on the upright ends of large pieces of less desireable firewood (knotty or less desireable for burning). On top of this I placed another piece of the same sort of log stacked end to end. I grouped several of these together for shade and moisture retention. I put the groups of shiitake stacks in areas shaded by holly, red bay, wax myrtle and pine trees.
So the clock is ticking. Maybe next year I will have another source of shiitakes.
By the way now is the time to inoculate your logs by whatever method you think will work best for you. But remember, if you want speed in your garden...plant radishes. Mushrooms are more of a marathon garden culture...but once they get started they produce for years.