Historic trees are a legally designated and protected category of landscape feature; they are trees (or groups or avenues of trees) that the nature conservation authorities have registered due to their exceptional importance and value.
Ostrava has 33 historic trees, including one pair of trees listed together as a single site. The majority of them are free-standing trees of outstanding aesthetic value. They include eight plane trees, six oaks and six beeches. Coniferous trees are represented by three species of the ginkgo tree and a dawn redwood (metasequoia) tree; these trees shed their leaves in the autumn like the larch. These species are known as living fossils due to their long history of development.
The oldest historic tree in Ostrava is a lime (linden) tree at the cemetery in the Nová Ves municipal district; its age is estimated at 500 years. The tree with the widest trunk in Ostrava (674 cm) is an ash tree in the Třebovice park; it has the widest trunk of any tree in the entire Moravian-Silesian Region.
Other trees with record dimensions include a chestnut tree in Ostrava-Zábřeh and two trees in the Třebovice park – a tulip tree and a beech tree.
The highest concentration of historic trees in Ostrava is at the Třebovice park (5 trees); the park is also a registered important landscape feature.