Hi Cliff, people were crucified on trees back then. They didn't have modern power saws like we have today, so they tied or nailed their hands to a piece of wood (a scraggly, crooked branch of some kind), then nailed that to the tree. That created the cross (the wood's horizontal piece against the tree's vertical trunk). Everything we see in pictures, movies, or even the finely sawed crosses in or outside some church buildings are not historically accurate or Biblically accurate.
I am troubled by the words of Peter stating that Jesus was killed by hanging from a tree. Please help me reconcile those words with the earlier scripture writings of Jesus dying on the cross.