In Paul Friedrich's book Proto-Indo-European Trees he identifies the "semantic primitives" of the Indo-European tribe of languages through a group of words that have not changed much through twelve thousand years - and those are tree names: especially birch, willow, adler, elm, ash, apple and beech (bher, wyt, alysos, ulmo, os, abul, bhago). Seed syllables, bija, of the life of the west.

The Practice of the Wild (ed. Counterpoint Press, 2010) - ISBN: 9781582436388