Großer Stein – Scree slope west of Burbach-Holzhausen

Above the villages of Holzhausen and Lützeln rises a densely wooded hill – the "Großer Stein", a relict of a long-extinct whose lava solidified to form multi-sided basalt columns. Over time, the wind and weather peeled off the softer types of rock, so that only the very weather-resistant basalt remained. Frost eventually split up the columns and the fragments rolled over the hilltop, forming the still-visible scree slope. The immediate vicinity of the basalt scree slopes holds a thriving nutrient-needy hardwood forest of Sycamore, Ash, Large-leaved Lime and individual Norway Maples, which is a very rare forest community in North Rhine-Westphalia. The scree forest can be seen at its best when the early-spring flowers like the white Wood Anemone and the Yellow Anemone, Hollowroot Birthwort and Spring Snowflake are in bloom. The forest around the Großer Stein is designated as natural forest and wilderness area. No commercial use may take place here.

The huge ancient trees are a paradise for woodpeckers. All six species native to North Rhine-Westphalia excavate their breeding cavities in the trees here, from the sparrow-sized Lesser Spotted Woodpecker to the crow-sized Black Woodpecker. After the woodpeckers have moved out, the cavities provide homes for numerous other species, such as owls, Stock Doves and forest bats.