Santiago Reyna and a broad team prepared a poster at tuber2013.com about the truffle industry in Spain.
Nowadays, although there are 27 nurseries producing truffle infected trees, just 15 of those produce over 200.000 trees every year. So plantations increase in order of 500 hectares annualy, although decreasing a bit due to the lack of public grants.
This data is quite true, as just in our nuseries in Barcelona, we will be producing around 40.000 trees with several truffle varieties this season. See in the pictures the ilex and coccifera (redish) germinating in our facilities.
Truffle farming has become the paradigm of rural development in most mountain areas in Spain. Farmers started to plant simply because they had nothing to loose. Note that cereal crops in these areas were about 1500kgs/ha, other crops like almonds give low harvests, and most years not even a harvest due to the late frosts…today, over 10.000 hectares are planted in Spain with Tuber melanosporum.
All the best,
Marcos S. Morcillo