The diameter on trees 15' or more is 7-8' which will stick out beyond column wall. What about 12' tree?

You can do a 10-12 feet tree. The tip can be close to the bottom of the railing. I don't know where you are planning to place the tree, but that size can work anywhere

10" angel, 12' to bottom of rail.

Well, how big is the largest ladder you own? ;)

I think the width is more of a concern than the height. It looks like there is not a lot of horizontal space in that area. I assume you will remove the ottoman?

A 12' is plenty high and I think you could even go with a 10'.

I'll assume because you know the dimensions, it is an artificial tree, the branches should bend if it's high quality tree. The back side where nobody can see could have the branches bent back into the tree by those extra inches you need in the corner. With lights and ornaments, it might just work.

There are also "half" trees that you could put right up agains the bookcase. Also, narrow-style trees.

Thank you all for the help. The ottoman doesn't go there; sorry grandchildren were here over holiday weekend. 7' x 7' open corner. I decided to go with 12' tree with 76" radius base and will bend the back,branches up. I will post pictures of finished product for your review.