The primeval forest in Haltiala was protected from logging in the 1930s and granted full protection status on 10 May 1984. The forest is home to diverse wildlife. Numerous polypores, other fungi and insects live in the rotten wood of old trees, either standing or fallen. The insects in turn attract birds, such as woodpeckers and treecreepers. The birdlife in the forest is indeed very rich, and even the demanding red-breasted flycatcher nests there. Mammals in the forest include badgers, foxes, squirrels and rabbits.

To help preserve the forest, visitors are asked to stick to the marked trails. There are three entrances, each with an information board.

Korpipolku nature trail 100 hectares

The Haltiala protected forest continues to the west along the Aarnipolku natural trail, which merges into the Korpipolku nature trail in the northwest corner of the primeval forest area. The Korpipolku nature trail was built in 2011 to highlight the theme of restoring forests into their natural state. The nature trail leads visitors deep into the forest. Information boards along the way describe how the previously drained forest has been restored into a wilderness area and the resulting changes that can be seen in the nature.

The forest undergoing restoration is not thinned, and dead trees are left to rot in peace. The focus of the project is on a lush forested valley covering 10 hectares that was drained since the early 1900s. The drainage ditches were dammed in 2005 to restore the natural water level.

The Korpipolku nature trail is 1.2 kilometres in length. A large information board can be found at each end, with smaller information boards along the trail itself. The trail is marked by conifer symbols and blue and yellow ribbons. The trail is narrow and is not maintained in wintertime. Wooden planks cover the wet areas. The trail is not suitable for strollers.

The forest restoration project has already enhanced the viability of many animals, plants and fungi in the area, and natural diversity is expected to further increase in the future.