ORIVESI | The historical Arboretum. The historical Hörtsänä’s Arboretum was founded in 1909. The lush park filled with hundreds of tree and plant species is located in the Onnistaipale village at Orivesi. Hörtsänä’s Arboretum has been selected as one of Finland’s hundred best parks. It was forgotten by the public for years, until a few years ago the overgrown park was brought back to life. Now the Arboretum is a fascinating mix of old and new and planted and wild plants.