The Peetri River Landscape Protection Area is renowned for its geological diversity.
Devonian limestone is only seen in Estonia as an outcrop on the banks of the Peetri River at Kalkahju. Beneath the rolling white stone is a cave with a spring, while the limestone and sandstone walls, river banks, meadows and forests provide a habitat for many protected plant species.
Karisöödi Park is home to an oak tree which is around 300 years old. It soars to a height of 23 metres, while its trunk measures 4.4 metres in circumference. Peetri River is the habitat of 15 species of fish (including the grayling and river trout) and a spawning site for salmon and sea trout.