Albert Barnes Commentary Acts 13:29

"And when they had fulfilled all things that were written of him, they took him down from the tree, and laid him in a tomb." — Acts 13:29 (ASV)

They took him down, and so on. This means it was done by the Jews; not by those who put him to death, but by Joseph of Arimathea, a Jew, and by Nicodemus, and their companions. Paul is speaking of what was done to Jesus by the Jews at Jerusalem; and he does not affirm that the same persons put him to death and laid him in a tomb, but that all this was done by Jews. See John 19:38-39.

The term "tree" in this context refers to the "cross."