The Ralisbroek, a rare seepage area

The Ralisbroek that we now experience as a forest was a wet grassland for a long time. The tram would still run through the meadows here in 1904. The groundwater is what is called 'seepage': it comes from higher areas and slides, as it were, on an impenetrable clay layer to it. At this low point, the water is pushed upwards.

From the interwar period onwards, the grassland was gradually converted to forest to reach the current forest area in the 1980s. We suspect that the forest evolved mainly into a planting of canada trees, but we are not sure. Today we see a lot of coppice of alder.

That the trousers were artificially dewatered can be deduced from the often straight course of the streams in the area to the Tieltse Motte and from a grid of small streams in some places near the Motte. The most important stream in the Ralis is the 'Grootspanseel'.

On the biological valuation map, the area is mapped as 'biologically very valuable'. On the wet clay soils one speaks of both an alluvial alder-ash forest, with pedunculate oak, willow and birch and as an acid oak forest with pedunculate oak and birch.

The area is largely a VEN area. This means that it belongs to the Flemish Ecological Network consisting of a selection of the most valuable and sensitive nature reserves in Flanders. A grassland along which we pass belongs to the 'historical permanent grasslands (HPG) and other permanent grasslands in Flanders, protected by nature legislation'.

The most striking (common) trees and shrubs are canada poplar, pedunculate oak, elder, hazel, alder, maple, occasionally a birch, rather exceptionally an ash, beech, holly, several blackberry species, ...

The wild holly that springs up here and there is an interesting species because it is characteristic of the Atlantic forests of the cool, humid climate. In eastern Europe, the species is no longer found in the wild in the forests.

As herbs we saw on the drier forest edge false sage, nailwort, ivy, male fern, female fern, a single needle fern, meadowsweet, dogdraf, look-without-look, a rare hop vine... In the wettest parts, rarefied sedge (Carex remota) appears to determine aspect. It is striking that nettle is present to a limited extent: an indication that nitrogen pollution is not massive. The high groundwater levels in the spring may prevent nettle – which usually has a faster vegetative development in the spring than other species – from running out considerably.

Jan Rymenams