All I know is that when I had a good producing woods I started finding the blacks first, and they moved out from there as the conditions in those areas (maybe 20 feet away) became acceptable. Then, as the conditions became favorable for the other types of mushrooms, they began showing up in areas and spreading out around the same way.
Think of it this way, the fungi is in the ground all over. When a certain spot get the right conditions they send up mushrooms there. Say you find a patch that is spread out over maybe a 20 foot circle. In two days you see no more there at all. However, if you go out around where the original patch was, you might fight several other patches which are very nearby or even touching the area where the first patch was. As conditions become more favorable, this process continues.
There are a few guys on here who understand this stuff much better than I do. This is only based upon my own observation.
I always remember what an older friend once told me when I was much younger. He said \"Its a lot harder to find a few mushrooms out of a few hundred, than it is to find a few dozen out of a few hundred thousand!\"