There are several requirements and experiences for a successfull graft, that are reviewed in the following from a practical point of view.
In coastal regions like the Portuguese Alentejo or Catalonian Empordà, grafting is usually performed directly in the field on young plantations, by specialised teams of skilled forest workers. In-nursery grafting on container-raised rootstocks is an alternative, not discussed here, for harsher climate conditions where in situ grafting has a low success rate due to unpredictable spring weather (rain, wind, or late frost in some years, early heat waves in others).
Several handbooks and guides are available online for further consultation.
The European Union defines, through several documents, the cultivation and collection of mushrooms and truffles as the primary product in agriculture. There are a number