no particular scriptural references (which may somehow disqualify the answer in your book), but in order to crucify to you not have to hang (ie - like you "hang" a picture)?

similarly, could the two phrases not mean the same thing?

meaning: if the cross was made from a tree could it not still be considered a tree? could the "tree" term not be symbolic of the cross?

is this a matter of the english used to "translate" the original terms?

just wondering.