Fodder trees and fodder shrubs have always played a significant role in feeding domestic animals. In fact, trees and shrubs are increasingly recognized as important components of animal feeding, particularly as suppliers of protein and especially in harsh environmental conditions. In such situations, the available grazing is not generally sufficient to meet the maintenance requirements of animals, at least for part of the year. This occurs, for example, in some mountainous regions and in the dry tropicswhere the grazing is also sometimes very degraded. Thus, in extensive animal production systems in the dry areas of Africa, it is generallye stimated that ligneous materials contribute up to 90% of production and account for 40-50% of the total available feed. Such figures illustrate the existing and urgent need not only for better knowledge but also for better use of such potential, particularly in the context of environmental degradation which is affecting our planet. On the other hand, in the humid tropics of Latin America, the South-cast Asia and Africa, foddersfrom trees and shrubs from leguminous species - are beginning to be utilized more dietary nitrogen supplements for ruminants. In this respect, new a significant move to look for new sources of protein from shrubs. However, given the increasing demand for forage and availability of low quality basal feed materials which require protein supplementation, high protein fodders from leguminous trees and shrubs could have a much more significant role in animal feeding systems throughout the developing world. In this respect, there is a need for more research to develop technically viable solutions. These solutions must also be economically and socially acceptable; they must preserve natural resources and protect the environment. In other words, the challenge is the sustainable development of fodder trees and shrubs.