Rensjöns Nature Reserve is a 691-hectare forest reserve.
The bedrock is mainly porphyry, providing fertile conditions with very thick forests and a rich ground flora. The reserve which can be characterized as a virgin region, comprising Rensjön and west of the rock Krokfljotbliket Trängsletpond. A forest road leads through the reserve from north to south with the mountain to the west and the flatter parts of the lake to the east. Diabase thoroughfare along the way affecting the flora and many rare plants including kransrams grow along streams and lush parties. In the hollows and valleys are extremely rich timber grankälar, age is estimated to be about 300 years, occasional pines is older than 500 years! The original reserve, deposited in 1937 covers the area east of the road. The forest which can be characterized as a pure virgin, because traces of logging do not exist. The same applies to the mountain Krokfljotbliket, whose head had once been entirely treeless, but now covered by a young pine forest. The word Blikk or plate means just treeless mountains. The only culture affected portion of the region lies west of the forest road, where collection of dead trees and coarse pine occurred in the 20's.
Faciliteter och service