André Zewen, an organic farmer from Fouhren, has around 1.150 walnut trees on 13 hectares alongside his 40 sheep. These trees produce up to 10 tons of walnuts. Two thirds of the harvested walnuts are sold in bags and with the other third he produces organic walnut oil. His nut production has been certified organic since 1998. Sustainable agriculture is particularly important to him. He practises a form of agroforestry, which is beneficial to biodiversity and the soil and has a positive influence on the microclimate.