Foresters can choose to fell all the trees in a generation that has reached maturity, and thus harvest a great quantity of wood. In this case, several species are planted in their stead. This method can allow animal and plant species to develop that appreciate very open spaces. Conversely, it is possible to exploit trees gradually, having selected them from an early age. Gaps in the tree cover are gradually filled, either by natural seeding or by planting. In this case, man’s efforts combine with nature’s.