In medieval times woods and forests were exploited in many ways (gathering dead wood for cooking, gathering berries, mushrooms, roots, pigs grazing, hunting/poaching, charcoal making, wood for houses and ships etc.) and some were private property of nobles and thus guarded. People were more aware of dangers of fires and didn' t permanently dwell in woods or forests. But, if a forest caught fire and threatened their homes they could only flee. Consider also that Europe was not so densely inhabitated as it is today. Sorry for my english, not mother tongue, but historian.