Black truffle of the Teruel holm-oak woods Food and drink · Corbalán, Comunidad de Teruel, Teruel The limestone holm oak woods of the sierra produce black winter truffle, harvested with a dog between December and March. In addition to the wild gathering, the comarca has truffle plantations that have fixed population in the villages. Photo: Diego Delso (CC BY-SA 3.0) What to see and do in Corbalán