Large areas of the park are covered in forests of the Macedonian fir ( a riddling hybrid fir species ) which is to be found only in this part of the Balkans .
Is also a remnant of the late Tertiary age .
Large areas of the park are covered in forests of the Macedonian fir ( a riddling hybrid fir species ) which is to be found only in this part of the Balkans and is also a remnant of the late Tertiary age .