SouthWestGardener

Good morning, new to the forum. Hopefully it's OK to post this here? I wonder if you're able to help me identify this tree. I don't know if I planted it or if it's grown of it's own accord. A single trunk around 4-5" diameter, grown to around 15'. Only one branch coming off the plant at around 4' from the ground. No other branches, which might suggest it's not a tree at all? Perhaps an overgrown shrub?? The bark is fairly smooth with a vertical pattern. I've tried apps to identify it, but none seem to be correct. Your help would be very much appreciated. I have attached photos of the trunk and the leaves.