I’m looking for some privacy screening, but it’s a narrow space so it needs to be something that is narrow at the bottom, but full at the top. I think the answer is a Columnar English Oak or a Columnar Armstrong Maple. So 1) Is a columnar oak/maple a good idea, or is there another tree I should be considering and 2) what are your thoughts on oak vs maple?
Of the two you mention the maple seems more appropriate. Another possibility might be a Japanese Tree Lilac
I had one and the branches started about 5′ off the ground.