What kind of trees do truffles grow around?

Answer 1

From Wikipedia...

The mycelia of truffles form symbiotic relationships with the roots of several tree species including beech, oak, birch, hornbeam, hazel and pine[5][6]. They prefer argillaceous or calcareous soils which are well drained and neutral or alkaline.[7][8] Truffles fruit throughout the year, depending on the species and can be found buried between the leaf litter and the soil. Their growth beneath the soil surface is thought to be an adaptation to resist predation, forest fire, drought, or severe cold.[citation needed] Toadstools above the surface of the soil are more vulnerable to destruction.