Naturschutzgebiet Oelinghauser Bruch: Protected Brook Valley and Wetland Forest in Hochsauerlandkreis

The reserve is primarily known for protecting a near-natural brook valley with alder and ash floodplain woodland in the Arnsberg part of the Sauerland. Its defining features are the meandering stream with a muddy to fine-gravel bed, spring zones and seepage lines along the slopes, and oak-mixed forest on the valley rim that grades into wet woodland fragments further down. A second distinctive element is the recovery of former alder-ash carr woodland. Parts of the historical carr have been cleared in the past, but re-planting and succession on potential carr sites, combined with the program of removing spruce regeneration from wet woodland areas, are intended to allow a diverse, structurally rich brook and floodplain forest to re-develop on the site.

The reserve was first designated in 1998 through the Arnsberg landscape plan adopted by the district council of the Hochsauerlandkreis. On that occasion it was established under the name Naturschutzgebiet Kerbtal und Laubmischwald In der Mark, with an initial area of about 6.2 hectares.

In 2021 the district council adopted a revised version of the Arnsberg landscape plan, through which the area was re-designated as a nature reserve under its present name, Naturschutzgebiet Oelinghauser Bruch, and its extent was substantially increased to its current size of roughly 9.8 hectares. Under the new designation the protection objectives were sharpened to give greater weight to the development of the forest communities and to securing habitats and species protected under Section 30 of the Federal Nature Conservation Act.

The reserve occupies a single small but sharply incised valley system. The defining landform is the Kerbtal itself, cut by a meandering brook with a muddy and locally fine-gravel bed into the surrounding terrain. The valley walls are steep; in places they descend directly to a narrow, often barely accessible floodplain, while elsewhere they open into more gradual slopes clothed in mixed deciduous forest.

The valley floor is a narrow floodplain, locally waterlogged or spring-influenced, dotted with seeps and minor rills. The floodplain carries alder and ash, and in some places young alder wet woodland. Above the valley floor the terrain rises into the drier slopes and plateau-like surroundings, which carry oak-mixed forest and locally small spruce stands. To the southeast the landscape shows the marks of past clearance, where former carr woodland has given way to more open ground now subject to restoration. Together these elements create a small but varied mosaic of valley, floodplain, slope forest, and recovering wetland forest within a very limited spatial footprint.

Ecologically, the reserve is dominated by deciduous forest ecosystems organised around water: brook, seeps, floodplain, and wet woodland. The brook corridor provides the hydrological backbone for the entire site, and the floodplain soils support alder and ash communities whose herb layers are characteristic of brook floodplains. Oak-mixed forest occupies the slopes and the higher ground, while former carr areas in the southeast carry fragments of the original vegetation alongside openings created by past clearing.

A defining ecological theme is the gradient from drier oak-dominated forest on the slopes to wet, waterlogged woodland along the brook and in spring zones. This gradient creates habitat for very different plant communities within a small distance and is central to the site's value as a refuge and connecting biotope for forest and brook species. The protection objectives explicitly emphasise that the site should act as a refuge habitat and as a stepping-stone between larger forest patches in the surrounding landscape.

The source material on the reserve focuses on vegetation, forest structure, and hydrology rather than on detailed wildlife records, so the wildlife content of the reserve is best framed ecologically rather than through a list of named species. The wet woodland, alder-ash stands, oak-mixed forest with veteran trees, and cavity-bearing trees provide nesting holes, deadwood habitat, and a varied herb and shrub structure that is meaningful for forest birds, small mammals, amphibians, and invertebrates typical of cool, moist brook valleys in the Sauerland.

The brook itself, with its near-natural flow regime, fine sediments, and brook-floodplain vegetation, is intended as a refuge for stream-dwelling invertebrate communities and for the smaller vertebrate life associated with wooded brooks in upland landscapes. The combination of structurally rich deciduous forest, seeps, and stream-side mosaic makes the site a coherent habitat complex even without specific named fauna being recorded in the available documentation.

Conservation value centers on the protection and restoration of near-natural floodplain and brook-side forest, of natural flowing waters and their communities, and of a structurally and species-rich deciduous forest complex with a high share of wet woodland. These objectives are explicitly stated in the landscape plan that underpins the reserve's designation.

Management measures are oriented toward restoring the site's natural forest composition. Initial plantings of alder and ash are being used on potential carr sites to re-establish appropriate woodland, while spruce, including naturally regenerating spruce, is being removed on a priority basis from wet woodland locations to allow succession toward deciduous cover. Forestry is permitted only under careful consideration of the sensitive site conditions and only with low-impact machinery. The reserve also serves the broader purpose of securing habitats and species protected under Section 30 of the Federal Nature Conservation Act, reinforcing its role as a refuge and connecting biotope in the regional landscape.

The reserve's standout features are its near-natural meandering brook and brook-side alder floodplain forest, set within a tightly incised Kerbtal north of Oelinghausen. The site is notable for the direct contact between oak-mixed forest on the slopes and wet alder-ash woodland, and for the gradient of seeps and spring zones that carry characteristic brook-floodplain vegetation through the valley.

Equally distinctive is the recovery story. Former alder-ash carr in the southeast has been largely cleared in the past, but surviving fragments and active restoration give the reserve a clear trajectory toward a richer, more species-rich wet woodland. Combined with the 2021 enlargement of the protected area, this makes Oelinghauser Bruch a compact but dynamic example of Sauerland brook-valley conservation.

The character of the reserve varies most strongly with the seasons through changes in water levels, foliage, and the visibility of forest structure. Spring and early summer bring high water in the brook and lush development of the floodplain herb layer, making the contrast between the wet valley floor and the surrounding oak-mixed slopes especially clear.

Late summer and autumn tend to give better visibility into the structure of the forest itself, with veteran beech and oak trees, cavity trees, and the pattern of old cuttings and regrowth standing out more clearly once the herb layer lowers. Winter reveals the shape of the Kerbtal most directly, when the bare branches show the line of the meandering brook and the mosaic of forest types along the slopes and floodplain. The reserve is small, so any visit is more about experiencing a coherent piece of Sauerland brook valley than about scale or infrastructure.