Solved What is this tree?

I have found several of these growing in the garden. Small trees but don’t know what kind. Does anyone recognise it?

 

It is possibly a silver birch sapling.
They are very prone to grow fast from seed, especially in sandy soil.

 

Thanks, @silversurfer, that makes sense. We have several silver birch in the garden, and I’ve just looked at their new leaves through the binoculars, exact match! We don’t have sandy soil here, but quite fertile acid soil.
Do you know how to mark this thread as ‘solved’?