I have been doing mushroom inoculation for the past few years and someone sent me these questions via email. I thought I would answer here rather than repeat myself over and over again in emails.
Can you advise on how late in the spring logs can be cut? I checked today and it seems that some sources indicate that early spring is best.
We usually try to cut our logs before the trees leaf out. It apparently helps the bark to stay attached longer, which in turn helps to keep the moisture in. One problem we have had with cutting the logs too early is that they can start drying out, which can make it harder for the mycelium to run through it. I have been told by some people to wait 2 weeks after cutting the logs before inoculating, but we have not always waited and it worked anyways.
Also can the poplar tree be used with good results? My farm has a plethora of them but I wonder about using them as I only found spotty references to their viability. I do have oak but it makes good firewood.
For shiitake, oak is the best. Hard maple is good. Poplar does not seem to be suitable from what I read, but I haven't tried it.
There seems to be oyster mushroom strains that do well of poplar (genus populus).
I like this chart for suitable species for different strains here
Here. Have a potato. I grew it in my armpit. And from my other armpit, this tiny ad: