The mushrooms of the upper Tirón mountains Food and drink · Fresneda de la Sierra Tirón, Montes de Oca, Burgos Image of Fresneda de la Sierra Tirón, not of the place itself. Saffron milk caps and boletus come out in autumn from the beech, oak and pine woods of the upper Tirón. Gathering, deeply rooted in the villages of the sierra, feeds the seasonal stews and has become one more economic resource. Photo: Rohappy458 (CC BY-SA 4.0) What to see and do in Fresneda de la Sierra Tirón