Heidelberg has been named “forest capital” since 2018.
The cultivation of foreign tree species is particularly successful when the climate and other site conditions match those of the country of origin as closely as possible. Heidelberg has a favourable climate for many exotic plants. Foreign tree species not only enrich the biodiversity in Heidelberg's urban forest but also help to make the forest climate-friendly. Trees such as the tulip tree, the Japanese larch, the black pine, and the large coastal fir occur only sporadically. Douglas firs and red oaks form the largest exotic tree population in Heidelberg, but they are already considered naturalized. The experts at the forestry office also no longer count the sweet chestnut as an exotic tree, since it came to Germany with the Romans 2,000 years ago.
The history of the 30 or so sequoia trees in Heidelberg's city forest, some of which are an impressive 40 meters high, can be traced back to 1876. At that time, the present arboretum (I) at the Sprunghöhe was already established, in which various exotic tree species - mainly from North America - can be found. The largest sequoia in this part of the forest was enclosed with a balancing circle of Robinia trunks to protect the sensitive root area from further damage.
Only a few hundred meters away from the jumping hill stands the Gaisberg tower. Built in 1876, the 13-meter-high tower can be climbed via 85 differently shaped steps on a spiral staircase attached to the outside. It was designed by the architect Fritz Seitz and built by the Heidelberg Castle Society. A special feature of the Gaisberg Tower is its style, an architectural rarity, also because it was built as dry masonry without mortar or other binding agents.
The Arboretum (II), a plantation of exotic trees (so-called "foreigners") extending from the Speyererhof Hospital to the Max Planck Institute for Nuclear Physics, was created in the last quarter of the 19th century as Speyererhof Park. Today, the park has a Far Eastern appearance. Visitors enter the landscaped area through a new entrance gate modelled on a Japanese torii. This structure symbolizes the transition from the secular to the sacred, marking the entrance to a sacred natural site. The two sculptures at the two main entrances to the north and south represent a globe carrying a tree and a tree carrying a globe.