High Fens

The High Fens (French: Hautes Fagnes; German: Hohes Venn) form the largest nature reserve in Belgium and one of the most important peatland ecosystems in Western Europe — a windswept raised bog plateau straddling the Belgian–German border in the eastern Ardennes, at an altitude of 650–694 metres above sea level. The reserve covers approximately 4,700 km² when including the broader Eifel nature park on the German side, with the strictly protected core Belgian zone encompassing 4,766 hectares of active blanket bog, wet heath, and old-growth forest. The plateau is dominated by vast carpets of sphagnum moss — the peat-forming organism — interspersed with cotton grass, cross-leaved heath, heather, and the carnivorous sundew (Drosera rotundifolia), which catches insects to supplement nutrients absent from the nutrient-poor peat. The High Fens peat body is up to 7 metres thick in places, representing an unbroken record of plant growth accumulating since the last ice age — 9,000 years of climate and vegetation history locked in the stratigraphy. The Signal de Botrange (694 m), the highest point in Belgium, stands at the northern edge of the reserve.

🌍 Geography and Ecosystem

The High Fens occupy the Vennplateau, a dissected upland of Devonian sandstone and quartzite that forms the highest part of the Belgian Ardennes. The acidic, impermeable bedrock prevents water drainage, creating the waterlogging conditions essential for peat formation. Annual precipitation exceeds 1,400 mm — among the highest in Belgium — and mist, low cloud, and rain are the norm for over 200 days per year, giving the plateau its distinctively atmospheric character. The peat bog acts as a vast natural water reservoir, slowly releasing water into the Warche, Our, and Vesdre rivers that drain toward the Meuse and ultimately the North Sea. The High Fens transition from active open bog at the plateau centre to birch–pine fen woodland (fêneaux) at the margins, then to the beech and oak forests of the lower Ardennes slopes — each zone supporting a distinct suite of fauna including black grouse, Eurasian curlew, common snipe, merlin, and the locally rare bog bush-cricket.

Brackvenn Raised Bog: The most intact section of active raised bog in the reserve, covering approximately 1,200 hectares of open sphagnum carpet with exceptional botanical diversity. Accessible only via the marked boardwalk system. The bog surface is deceptive — it appears firm but the waterlogged sphagnum can be 3–4 metres deep under the moss layer. Leaving the boardwalk is prohibited and dangerous.
Signal de Botrange (694 m): Belgium's highest point, marked by a stone tower built in 1932 that adds 6 metres to the natural altitude. The surrounding open plateau gives panoramic views across the fen landscape in all directions on clear days, though cloud and mist are the more common conditions. A modest tourism tower provides context about the plateau ecology and history.
Baraque Michel Historic Way-Station: An 18th-century stone refuge built in 1808 by Michel Schmitz to shelter travellers crossing the notorious Vennplateau in winter — the high fen was historically a major obstacle on the road between Liège and Aachen, and multiple travellers died of exposure in winter storms before the refuge was built. The building still stands and now houses a café and small historical exhibition.
Warche Valley Gorges: The rivers draining from the High Fens have carved deep, narrow gorges through the Ardennes sandstone below the plateau edge, particularly the Warche near Malmedy and the Our near Sankt-Vith. The valley walls support old-growth oak and beech forest with populations of wild boar, red deer, and roe deer. The contrast between the open, wind-exposed plateau and the enclosed, sheltered valley floors exemplifies the ecological diversity compressed into a small geographical area.

📜 History and Cultural Significance

The High Fens plateau was virtually uninhabited throughout history due to its harsh climate, poor soils, and impenetrable bog terrain — a 'no-man's-land' at the frontier between the Low Countries and the German territories. Early medieval documents describe the Vennplateau as a wilderness (the Latinised terra inculta) used only as a boundary marker between ecclesiastical territories. The Roman road from Tongeren to Cologne crossed the plateau's southern edge, and sections of paved Roman road surface are preserved under the peat in several locations, discovered by chance during peat cutting in the 20th century. The area was the subject of a major boundary dispute between the Belgian and German governments following World War I — the Treaties of Versailles (1919) and Eupen-Malmedy (1920) transferred the German-speaking Eupen-Malmedy district, including part of the Vennplateau, to Belgium, creating the present mixed French-German-speaking character of the region.

The first serious peat-cutting operations began in the 17th century, when peat was commercially extracted for fuel and exported to the cities of Liège and Aachen. By the late 19th century, large-scale drainage and afforestation programmes had converted significant areas of the original bog to spruce plantation. The High Fens Nature Reserve was established in 1957, halting further peat cutting, and subsequent decades have seen the laborious process of rewilding: removing spruce plantations, blocking drainage ditches (over 500 km of ditches have been blocked since 1990), and allowing the natural hydrological regime to recover. The reserve is today one of Western Europe's largest active peatland restoration projects.

🏃 Activities and Attractions

The High Fens reward visitors who embrace the austere, spacious atmosphere of a northern peatland — dramatic weather, vast open skies, and a botanical landscape of extraordinary subtlety that reveals its richness slowly to those who take time to look closely.

Boardwalk Trail Walks: The reserve maintains approximately 9 km of wooden boardwalk across the most sensitive bog terrain, including the flagship Brackvenn circuit (4.5 km return from the Botrange information centre). The boardwalks are designed to allow intimate engagement with the bog surface without causing damage — moss, sundew, cotton grass, and crowberry are visible within arm's reach. Morning visits in summer are recommended for dew on spider webs and bog rosemary in flower.
Black Grouse Watching: The High Fens holds one of Belgium's last remaining black grouse (Tetrao tetrix) populations, with approximately 50–70 males counted in recent surveys. The lek (communal display ground) is active from March to May at dawn, and guided dawn walks from the Botrange centre are organised weekly during this period. Binoculars are essential; noise and sudden movements will abort the display.
Cross-Country Skiing: In years with sufficient snowfall — which historically occurred reliably but has become less predictable with climate warming — the High Fens provides the only significant cross-country skiing terrain in Belgium. A network of prepared tracks extends across the plateau from Botrange and Baraque Michel, attracting day-visitors from Liège, Aachen, and Cologne when conditions permit. Snow cover of at least 30 cm is typically sufficient for 2–3 weeks in January or February in good years.
Long-Distance Walking (GR 56 and RAVeL): The GR 56 European long-distance walking route crosses the High Fens as part of its arc through the Belgian Ardennes, and several local waymarked routes (RAVeL) connect the plateau to the valley villages of Malmedy, Stavelot, and Eupen. The 60-km Vennbahn cycle trail follows a converted former railway through the landscape bordering the reserve, passing through German-speaking Belgium and into Germany.
Geology and Archaeology Trail: A self-guided trail near Baraque Michel visits the preserved sections of Roman road buried under the peat, the ruins of 18th-century peat-cutting operations, and information panels explaining the formation of raised bog and its role as a carbon store. The trail takes approximately 2 hours and requires waterproof footwear.

💡 Travel Tips

Getting There: The High Fens plateau is in eastern Belgium near the city of Liège. The main visitor access points are the Signal de Botrange (from Malmedy on N68, approximately 15 km) and the Baraque Michel crossroads (from Spa on N676, approximately 12 km). Spa is the nearest town with significant accommodation and services, 15 km to the west. From Brussels, the drive is approximately 2 hours (160 km) via the E42. Public transport is limited — a seasonal bus service connects Malmedy to the plateau on weekends in summer.

Best Season: September–October for heather in full bloom (purple moorland carpet) and early autumn colours in the valley forests. April–May for black grouse lek and first bog flowers. January–February for snow landscapes and possible cross-country skiing. Avoid August bank holidays when parking is severely congested.

What to Pack: Waterproof jacket and trousers are essential at all times of year — the plateau generates its own precipitation and conditions change within minutes. Sturdy waterproof boots for off-boardwalk sections of the wider trail network. Binoculars for birdwatching. The plateau can be 8–10°C cooler than the surrounding valleys even in summer.

Regulations: The core bog zone is accessible only on designated boardwalks and marked paths. Entry off the boardwalk is prohibited for ecological reasons and is also genuinely dangerous — sphagnum bogs can swallow a person. Dogs must be on lead throughout the reserve. The reserve is divided into zones (A=strictly protected, B=controlled access), and the most sensitive sections require a guided tour to visit.

🌱 Conservation

The High Fens is one of Western Europe's most ambitious peatland restoration projects and one of the most important carbon storage landscapes in Belgium — the reserve's peat body contains an estimated 5 million tonnes of stored carbon, more than all Belgian forests combined. Peatlands store carbon at rates far exceeding forests and are critical natural infrastructure in climate regulation. The primary conservation threat is the drying of the peat caused by decades of historical drainage: over 500 km of drainage ditches were cut across the plateau between the 18th and 20th centuries to support peat extraction and timber plantation, and the resulting desiccation has caused oxidation and carbon release. The ditch-blocking programme coordinated by the Walloon Nature and Forest Agency has blocked over 500 km of drains since 1990, raising the water table across large sections of the plateau and enabling active sphagnum regrowth.

Climate change poses an existential challenge to the High Fens ecosystem: the plateau has warmed by approximately 1.5°C since 1950, and the trend toward warmer, drier summers is increasing the frequency of bog surface fires — historically very rare — which can burn through the dry sphagnum moss layer and release centuries of stored carbon in hours. Three major fires have occurred since 2011, the largest (2011) burning 570 hectares of the core bog zone. Fire prevention infrastructure including water retention pools and firebreak tracks has been installed, and the Belgian Air Component provides helicopter water-bombing support during periods of fire risk. The expansion of invasive birch into the open bog margins is being controlled by mechanical clearance, and the recovery of black grouse populations is supported by predator management on the lek sites.

✨ Conclusion

The High Fens are Belgium's great surprise: a landscape of genuine wildness and ecological depth, hidden in plain sight within a few hours of half the population of Western Europe. The silence on the plateau on a misty October morning — broken only by the call of a curlew and the wind across the cotton grass — is as complete as anything the far north of Scandinavia offers, and the knowledge that this ancient peat body has been forming since before the pyramids were built gives the landscape a temporal weight that no human monument in Belgium can match.