The hollows of Häntälä are the most famous part of the traditional enviroment around the Rekijoki River. Downriver, in the village of Isohuhta, in the municipality of Kiikala, the muddy clay bed of the river is lined by meadows and old pastures. Higher up, one can see the edge of the forest standing tall and thick. There begins the Riihikoski Forest, a conservation area of ten hectares, acquired by the Finnish Natural Heritage Foundation in 2004.

The foundation had the forest placed under protection according to the Nature Conservation Act, but the forest, as well as the meadows nearby, also belongs to the Rekijoki area under the Natura 2000 programme. Belonging to this EU programme would not, however, been enough to protect the forest completely because the forest would not have been completely safe from cuttings, for instance. The risk faded away, however, when the Finnish Natural Heritage Foundation bought the area since the protection completed under the Nature Conservation Act was absolute.

The Riihikoski Forest is located on a slope opening to the west. While it is spruces that dominate the area, there are also some sturdy old pine trees growing here and there. Someone walking in the forest might find it surprising to see small woods of grey alders there as well. The terrain is almost completely made up of grove-like heath and different kinds of heaths with some demanding species flourishing as undergrowth.

The clay slopes are grooved by deep brook valleys, the slopes of which are growing clustered bellflowers and cinnamon roses in the shade of junipers.