The Dünnwalder forest is around 410 hectares large urban forest in the northeast of Cologne . It is part of the Bergische Heideterrasse . In addition to the Dünnwald district , over which it essentially extends, it also borders on Höhenhaus and Dellbrück . It extends into the urban areas of Bergisch Gladbach and Leverkusen . In Cologne, the Dünnwald forest is an important part of the green belt on the right bank of the Rhine, alongside the Königsforst .
The area known today as the “Dünnwalder Wald” is the original area of the Dünnwalder and Thurner Heide, the municipality heaths (“Gemeen”) of the surrounding villages. The Prussian first recording from 1844 shows large open heathland areas here. As early as 1893 (Prussian new admission), large parts of these heaths were afforested with the general staff of the Scots pine (Pinus sylvestris), which is not native to the Lower Rhine Bay .
Due to agriculture and military use, for example in the nature reserve Dellbrücker Heide and in the area of the Schlebusch dunes, valuable and species-rich open habitats were selectively preserved from the second wave of afforestation of the post-war period. But building, afforestation, gravel mining and subsequent recultivation almost completely destroyed them by the 1980s at the latest. Parts of Dünnwalder and Thurner Heide were still considered to be one of the most important locust occurrences in the state of North Rhine-Westphalia in the 1970s. a. with the red-winged wasteland cricket, the field cricket or the wart-biter. These species have now disappeared, their habitats have disappeared.
In 1956, the Cologne city administration, in cooperation with the Schutzgemeinschaft Deutscher Wald, set up an extensive reforestation program for the urban area on the right bank of the Rhine in order to better shield the residential areas from exhaust gases and dust.
Originally the forest was mainly laid out as a mixed forest with a large number of coniferous forest pieces. This is due to the fact that the forest area is located on the middle terrace on the right bank of the Rhine , where the soil consists mainly of sand and gravel and there are only a few narrow strips with better soil, which also offer better conditions for vegetation. Pine and birch trees thrive best on the remaining rather barren soil . It was not until several decades later that the forest administration began to gradually transform the Dünnwald forest into a deciduous forest . Because of the nature of the forest, there are few natural nesting opportunities for birds, so many nesting boxes were hung here. In addition to well-tended paths, the Dünnwald forest also offers walkers and hikers a number of shelters . On April 21, 1996, there was a not inconsiderable forest fire , which only burned down a small part of the forest, which has now fully recovered.
The “Am Hornpottweg” nature reserve is located in the Dünnwald forest , a former gravel pit that, a few years after its closure, developed into a particularly valuable biotope in the 1980s, offering a habitat for numerous animal and especially bird species. Here you can see not only native birds, but also numerous migratory birds that use the pit as their preferred resting place. The pit is surrounded by a circular path, from which the visitor has ideal opportunities for observation. The nature reserve on Hornpottweg is located on the northern edge of the Dünnwald forest, near the city limits of Leverkusen- Schlebusch .
Close to the residential areas in Cologne-Dünnwald, on the edge of the forest , lies the Dünnwalder Wildlife Park , which was founded at the same time as the afforestation. The wildlife park is a freely accessible area of around 20 hectares, on which several species of wild animals live in enclosures, including wild boar , fallow deer , European mouflons and bison that have settled here from Poland . The Dünnwalder Wildlife Park can also be explored during one of the free guided tours that take place every second Wednesday of the month at 2 p.m. near the Kalkweg / Dünnwalder Mauspfad entrance . Near the wildlife park, on the other side of the Dünnwalder Mauspfades, is the so-called arboretum , a 4.3-hectare area that has been used by the German Forest Protection Association as a collection of some valuable trees and bushes since the early 1960s. Here you can see plants from moderate climatic zones that are otherwise not found in German forests, such as pigeon tree , magnolia , tulip tree , beech , sequoia or cedar . One of the aims of the arboretum is to investigate the possibilities of planting such trees in German forests.
- Karl E. Quirl and Hermann Grün (eds.): Dünnwald then and now. Cologne 1993, p. 121
- M. Kramer, K. Kraatz: The locusts of Cologne. In: Decheniana-Beihefte, 35, Bonn 1996
- Hermann Josef Roth (ed.): Cologne nature guide. Wienand, Cologne 1991, ISBN 3-87909-256-7 , pp. 275-276.
- M. Weitzel: To the straight wing fauna of the Dellbrücker Heide in Cologne. In: Decheniana-Beihefte, 35, Bonn 1996