PIE *Heh3s "birch tree/ash tree" is the source of Proto-Germanic *asko meaning "ash, ahes" as in that which fire leaves behind

In addition to what the title says, I describe the root meanings of PIE *heh3s and the PIE roots that it is a variant of. In the second edition uploaded almost two hours later, I describe that the "ash" meaning could have come mainly from the white bark of the birch tree, since PIE *heh3s likely originally meant "birch tree". 

In the third edition, I derive *kwetwores from the earlier meanings "birch tree; axis mundi" directly linked since very ancient times with the Northern Cross, the Cygnus constellation (for example, Tungusic shamans placed wooden swans in a form similar to a cross on top of long poles of birch wood which stood for the Axis Mundi/World Tree). From the four arms of the Northern Cross (explaining best why the swastika was directly a symbol of the Axis Mundi) came the meaning "four". So *kwetwores is from *kwetu, a variant of *gwetu- meaning "birch tree"; plus the suffixes "-or-es". 

In the 4th edition, I have added a new Part 3 where I have added excellent additional evidence for my theory that *kwetwores is a variant of *gwetu, and I show that the Dithur- of Dithurambos most likely derives from *kwetwores="tree; pole of wood" via Phrygian/Brygian, with Phrygian cognates detailed.