American Chestnut Foundation worker harvesting nuts from an American Chestnut (Castanea dentata) in Nashua, New Hampshire, USA. Bags were placed on the female flowers in early summer to prevent them from being pollinated by the wrong pollen. A few weeks later each flower was covered with pollen from crossbred chestnut trees that show signs of resistance to Chestnut Blight. Flowers are then covered again to protect them over the summer.