The Arboretum, the tree collection in Tierpark Sababurg, is continuously planted with the Trees of the Year. Since 1989, the "Baum des Jahres" (Tree of the Year) campaign has been announcing a specific tree species each year.

The first tree to be planted in the Arboretum at Tierpark Sababurg is the Tree of the Year 1989: the Pedunculate Oak.

In 2011, the "Schutzgemeinschaft Deutscher Wald" (German Forest Protection Association) planted 22 Trees of the Year in Tierpark Sababurg  to commemorate the International Year of Forests. The newly established Arboretum contributes to the conservation of biodiversity and the preservation of rare species. Each tree is accompanied by a clear and beautifully designed information board providing key facts about the respective tree. The Arboretum can also be used as an educational tree trail, offering the opportunity to provide hands-on knowledge, especially to schoolchildren. It is becoming a unique collection of trees in Hesse, providing an overview of different native tree species.

The Arboretum starts at the outdoor enclosures to the right of the farm and continues along the zoo wall (starting from the left of the wolf enclosure).