Farmers actually only pollard trees during dry seasons, when the hay harvest falls short of their needs. From mid-July through September’s end farmers harvest leaf fodder from hedge maple (Acer campestre), Norway maple (A. Platinoides), hornbeam (Carpins betulus), oriental hornbeam (C. orientalis), ash (Fraxinus excelsior), black mulberry (Morus nigra), oak (Quercus spp. – except for Q. cerris which is the animals do not eat), white willow (Salix alba), large leaved linden (Tilia platyphyllos) and elm (Ulmus spp.). Only in years of severe feed shortage do they use European beech (Fagus sylvatica), while black alder (Alnus glutinosa) remains even less common. They collect the nuts from hazel (Corylus avellana) and use the leaves medicinally to treat prostate problems and kidney disease in humans.