Reforestation measures, planting for nature conservation, as well as spontaneous processes of succession in declining regions such as the Ruhrge- biet are leading to increasing forestation of developed areas. Even if the increase of wild woodlands in urban-industrial areas is unquestionably valuable, they do not have to be protected at any cost, their natural development needs not stay free of designing intervention. On the contrary, the denseness and closed-ness of spontaneous woodlands require design interventions in the places where the woodlands meet developed areas in order to open up the space, create lines of sight, and allow public use.
In addition to semi-natural cultivation, the development of artificial visions of the woodland, especially along the borders of developed areas, increases in significance. The woodlands no longer stand in opposition to developed areas, but rather are a part of the urban-industrial landscape. The “natural woodland” gives way to more transparent forms such as tree plantations, extensively maintained park landscapes, or agricultural land. A mosaic of open spaces and woodland types requiring differing intensities of care from wild industrial woodlands to production tree plantations open for recreation activities is possible by combining types.