At one stage I was the northern most producer of truffles (very few produced actually but I only had 40 trees and didn't really look after them to the utmost detail) in the southern hemisphere, then a guy 150km further north, and in soil that was near total sand, got some to grow. This was totally unexpected.
It seems the conditions required are not quite so special as thought, and some totally unsuited conditions (as previously thought) might be good due to reduced competition from other fungi.
The action of inoculating trees is simple as well, get a ripe couple of real truffles, blender them up and pour it over the small saplings in pots, if the mycorrhizal sets in you can see it as white bits on the roots. (I think you need two, but not even sure on that).
A wide range of trees will work, oak, hazel, cork to name a few. There is a preferred pH range for the soil, as would be expected for all fungi pH has a strong role to play.
There has been a lot of secrecy enshrouding the whole game for a long time.
I refer only to Tuber melanosporum in the above, I am not sure anyone has been able to get the white truffles growing out of the wild, there will be some special condition or symbiosis with an animal or something that is needed, but not understood yet.