As parallel to industrialization and increasing population, pressures on natural resources have rised, soil, water and air have been polluted. These problems threaten the human. So, environmental protection or in awider meaning nature conservation became a very important duty for the human in this century. The duty is a special action against eradication of living base for the organisms Forest ecosystems are of course economical natural resources. The ecosystem is a monotonous forest area by compositions, characteristics and relationsihips of the main elements within the forest. In the article, firstly, forest ecosystems and their functions were examined, then, importance of forest as natural resources, their roles for preventing risk of climatically changes, and contribution of forests for sustainable development within Turkiye were studied.