The oldest oak forest that is over 300 years old, blossoms in Širvintas forest, Meteliai Regional Park. Two trees of this forest, which grow along the road to Seirija – Simnas – have been declared natural heritage sites.

The Great Širvintas Oak is a botanical natural heritage object. The oak is of exceptional age and size, growing in Lazdijai district, Seirijai eldership, in the territory of Veisiejai SFE Seirijai Forest District. The height of the Great Širvintas Oak is 31 m, its volume – 5 m.

The tree was declared state protected in 2003.

The Horned Širvintas Oak – a botanical natural heritage object, oak of exceptional age and dimensions as well, memorial tree of Meteliai Regional Park. It grows in Lazdijai district, Širvintas forest of Veisiejai Forest enterprise. The height of hollow Horned Širvintas oak is 29 m, its volume is 4.4 m.

The tree was declared state protected in 2002.