The aim of the diploma thesis is to describe and compare the possibilities of practical use of woodcocks in forestry and agricultural practice on the territory of Slovakia and worldwide. The theoretical part of the diploma thesis deals with the brief characteristics of mushrooms, their nutrition, the systematic classification and the detailed description of the oyster mushroom (Pleurotus ostreatus) and the reishi mushroom (Ganoderma lucidum). Subsequently, waste from forestry and agricultural activities is defined and the possibilities of the ecological use of these wastes are described. In the practical part we have devoted our own research to the appropriate use of wood-decay fungi as decomposers of organic waste, produced by forestry and agricultural activities. We have chosen an intensive way of growing on woods of deciduous trees of Fagus sylvatica, Quercus robur and Tilia cordata. We have divided the experiment into an internal attempt and an external attempt. The result of the experiment was the evaluation of mycelium growth, primordial formation and growth of the fruit body of the oyster mushroom (Pleurotus ostreatus) and the reishi mushroom (Ganoderma lucidum).