But the name “Yddal” is derived from another tree than pine. The name stems from "yr", the old Norwegian word for "Yew tree". There is still Yew to be found in this area. Some of the trees have trunks up to a metre thick, often with rot in the wood, or they may be hollow. Yew such as these must be very old.
It is easy to get lost in these forests, but the rivers and lakes are a good help for navigating. Paths lead into the area from Lygre, but they are of varying quality. The waterways have been used previously for floating timber. Old logs, remains of dams and an old sawmill tell us of earlier times. It was not always easy to get the timber out; the terrain is quite hilly. The old lumber men have left their mark, but in many places the pine forests have grown back.
In rugged, steep terrain and on the crests of hills where logs were not taken out, there are now large and old trees with much dead wood, as one would find in a virgin forest. Lygresåsen is a good place to experience this old type of pine forest. Here, the pine forest lies like a carpet over the whole horizon. The feeling of the wilderness this gives is difficult to find in any other forest area in Hordaland. The area is also protected, as a part of one of the biggest nature reserves in West Norway.
Yddal has a rich plant life, with many species that are rare elsewhere in the district. On the many small, nutrient rich bogs, one sees a good many of these rarer species, among them broad-leaved cottongrass, marsh clubmoss, cotton deergrass, moor rush and dwarf birch. Other rare plants are found higher up on the slope. If you are lucky, you may see the orchids small white orchid and butterfly orchid on the rock ledges.
