Well, all that was written by Luke, so that is really just ONE source, then there is the logistics of the matter ( multiple trees, at least 3, trees that are strong enough and hig enough, etc) but that passage from Luke 23:31 is a bit of a stretch there:
26 As they led him away, they seized a man, Simon of Cyrene, who was coming from the country, and they laid the cross on him, and made him carry it behind Jesus. 27 A great number of the people followed him, and among them were women who were beating their breasts and wailing for him. 28 But Jesus turned to them and said, “Daughters of Jerusalem, do not weep for me, but weep for yourselves and for your children. 29 For the days are surely coming when they will say, ‘Blessed are the barren, and the wombs that never bore, and the breasts that never nursed.’ 30 Then they will begin to say to the mountains, ‘Fall on us’; and to the hills, ‘Cover us.’ 31 For if they do this when the wood is green, what will happen when it is dry?”
Jesus seems to be referring to if they do these things NOW, later will be far worse.