The Hof-ter-Musschen or Ferme des Moineaux and its surroundings constitute a semi-natural site of 10 ha, classified since 1994 as being of high biological value.

It brings together the marshes, wet meadows, wooded areas, the Brabant farm and the windmill which form a remarkable open-air museum of what once was the rural landscape of Greater Brussels. In the past, the meadows extended to this location over more than 50 ha (current UCL site).

Established for nearly 200 years on the eutrophic alluviums of the Woluwe, the Hof-ter-Musschen marshy complex offers a remarkable sample of plant species and semi-natural associations that characterized the alluvial plains of the Senne basin. There are the following groups:

• a grouping of small hogweeds and populations of the marshes at the edge of the stream;
• a high meadow with aquatic glycery;
• a magnocaricae and a marshy alder grove with swamp sedge;
• a short meadow with red fescue;
• willows cut in tadpole delimiting the meadows.