the soil comes into the swamp. >> local families need the grass for their livestock. they're already having trouble finding fodder, since the hills have been largely deforested. without trees, the soil erods. -- erodes. it's a huge problem across rwanda, and in this region. the silt endangers the marsh and lakes. francis musoke meets regularly with local farmers. but there are no simple solutions. people here know that damaging the environment will also destroy their livelihoods. >> twenty years ago there were tall trees and lots of forest here. the people cut down a lot of trees. now they're all in need of firewood. the population keeps growing. there aren't many animals here anymore. one approach is reforestation. planting new trees could halt the erosion and be useful in other ways. the hazelnut shrubs, for example, can be used in raised-bed gardening. the branches serve as fodder, so the cows no longer need grass from the marsh. >> initially they thought trees were not good for the gardens. they thought the trees were competing with their crops. but with time, with the sensitization and education they have now learned that trees can co-exist with the gardens and their crops. >> the in