Rowan maintenance - any advice?

I planted a beautiful rowan in the far corner of my garden, well away from my house. It has grown up in 4 years and is now about 12 foot high. It has a lot of lower branches below waist height. Can I simple saw these off to make the trunk taller, or will they fall off later? Most rowans in my area have long trunks.

I’ve no problem with it reaching say 30 foot tall, but I want a tree, not a shrub.

 

Hi @MrsRake I would trim them off neatly - I did the same to raise the crown of an acer in my previous garden - made it less shrubby and more tree-y. Just be careful about doing it nicely - I understand they don't recommend treating the cut ends any more, just leaving them to seal themselves.