as the habitat consists of bogs, fire is a major hazard during the drought period, when fens is closed except for a small fen area near poleur. triangular signs painted in red are fixed at the fire hazard locations. in april 2011, in a fire that broke out in the high fens, of land were destroyed. stated to be the biggest ever fire in the fens, 300 fire fighters supported by a helicopter were involved in dousing and controlling the fires.