This article discusses the collective names of trees used in the Scandinavian languages, as well as the formation process of similar collective names in Eastern and Western Germanic. It should be emphasized that the Northern Germanic languages used the suffix *-ijan for creating collective nouns which denote ‘a group of trees’, e. g. ON. birki n. coll. ‘birch forest’, Icel. birki ‘birch forest; birch’, Norw. birki ‘birch forest’, Swed. björke ‘birch forest, birch grove’ (< PG. *berkijan n. coll. ‘a group of birches, birch forest, birch grove’ ← PG. *berkō f. ‘birch, Betula’). The same suffix denoting collectivity and originating from the Proto-Indo-European language is also present as *-ьje in most Slavic languages, cf. Ru. dial. берéзье n. coll. ‘birch forest, birch twigs’; OPol. brzezie n. ‘birch grove or forest’; Cz. březí n. ‘small birch-grove’, also břízí n. ‘birch twigs, birch-wood’; Slovak brezie n. ‘small birch-forest, birch-grove’; SC. bre ̑ z je n. coll. ‘birch forest’, Sloven. brẹ̑ zje n. ‘id.’ (< PSl. *berzьje n. coll. ‘group of birches, birch forest, birchgrove’ ← PSl. *bȅrza f. ‘birch, Betula’). Further possible traces of the same suffix can be found in the Baltic languages (cf. OPrus. pannean n. ‘mossy fen’ vs. Go. fani n. ‘mud’, OSax. feni n. ‘fen’) suggesting that the Proto-Indo-European collective suffix can be reconstructed as *-ii̯ o m (n. coll.). It seems probable that some northern Indo-European tribes used the derivative word *bhe r ̥h 2 ĝ i i̯ o m (n.) to denote ‘a group of birch trees’, especially ‘a birch grove’ or ‘a birch forest’.
Habrajska G., Rychło M., Witczak K. T. COLLECTIVE NOUNS DENOTING TREES IN THE SCANDINAVIAN LANGUAGES