Trees also provide farmers with materials for fence posts, poles and farm implements. Nearly 240 million pastoralists around the world depend mainly on tree fodder to feed their animals. In Costa Rica, dairy farmers retain scattered alder trees in their pastures because the trees improve the forage quality of the grass, resulting in greater milk production. Trees provide shade for livestock, important to their health and productivity in hot, dry areas. Of growing importance is the role forests play as storehouses of biodiversity, potentially very important in future crop breeding and pest and disease management programs.
Forests also have significant links with inland and marine fisheries.
Rivers and streams are rich fishing grounds for local populations. Forests regulate the volume and fluctuations of streamflows and provide a shaded riparian environment favourable for the development of smaller life forms which fish feed on. The mangrove swamps in southern India provide habitats for many fish species, especially shrimps. The fish catch enriches protein-deficient diets and generates household income. Economic Opportunities Cash income provides the buying power to purchase food when agriculture is not practised or when crops fail.