ENThe present article represents the first part of a planned scries of studies analyzing gradually the arboreal terminology in all Indo-European branches. Besides the survey of the known lexical data and existing etymologies there arc proposed some new solutions here, c.g. Balt *aniolis ‘oak’ consisting of the prefix *an(t) (cf. antkainis ‘Gebirge’: kalnas ‘Berg’) & the base attested in Lith žuolis ‘Baumstamm’.