The Greek island of Kea suffers, like many places.Healthy trees are better at preventing soil erosion and oak forests that provide a sustainable income for farmers are more likely to be protected and even extended.The ancient oak forests are the source of giant acorn caps, known locally as Hamada .Marcie Mayer, an American who is married to a local man, had the idea to use crowdfunding to publicize the acorns and purchase machinery to help in harvesting and preparing them.Kea's acorns became unwanted and neglected.Acorn caps are boiled in water and animal skins are then soaked in the resulting liquid to help in the creation of leather clothes.Marcie produces her own acorn cookies, which are sold on the island and exported to shops all over Europe.Although acorns have an unpleasant, bitter flavor, this can be removed by soaking them in water.Marcie has also shown the people of the island that acorns offer a healthy source of food.Acorn caps are natural and produce a better quality of leather than chemicals.