The process of repopulating denuded forests and woodlands with trees. It is the solution to deforestation caused by logging and other human means of destroying areas once populated by tree cover. To maintain a sustainable forest industry, reforestation is necessary. In temperate areas, reforestation can occur naturally. Native US hardwood forests, for instance, are so resilient that when left alone they quickly re-grow themselves. In other areas and climactic as well as environmental conditions, reforestation can only be done through tree-planting efforts.