Most associate Åsane with ridges, naturally enough (the Norwegian word for "ridge" is "Ås"). A lesser noticed trait in the landscape are the unusual flat areas that lie between the ridges. The Dalselva River, which was channeled at the end of the 1950s, runs down only 2.5 metres from Lake Langavatnet by Vågsbotn to Flatevad, where it goes over into rapids by Fossekleiva. The layers of gneiss stand nearly vertically, and the mountain surface is so even that one might think it had been planed with a planer.
There is no place in Hordaland where there are so many over-wintering song swans as in Tjeldstømarka. And there are few places in the county that have had this birdfowl as a guest for as long.
Lysekloster was the largest agricultural property in the country when it was phased out during the Reformation in 1537. In its prime this cloister encompassed two-thirds of all the farms in Os. The monks introduced and cultivated new plant species and it was probably they who stocked the waters with fish not indigenous to the area. This legacy from the Middle Ages has left a lasting mark.
The area around Lysekloster is one of the most popular places in Hordaland for picking mushrooms. The large variety of mushrooms probably stems from the varied, old, cultural landscape which has a lot of open grazing areas and several types of fir- and deciduous forests.
On Sandviksfjellet there are old boulders that have been made into mountains. The stones have been stretched out or squeezed together between huge slabs of rock, during slow, but powerfulprocesses of transport. This conglomerate shows, in quite a special way, the enormous powers that were active during the collision between Norway and Greenland over 400 million years ago.