Many plant nurseries and garden centres sell multi-stem versions; trees with several stems radiating out from the base, giving the impression that there’s more than one tree to give you an instant woodland effect.
Betula utilis var. jacquemontii is the most widely available multi-stem birch with stunning white bark to brighten the dullest winter day. They can be expensive, so a cheap hack is to plant 3 single stem birch together with the trunks slightly angled outwards and hey presto you have the impression of a multi-stem tree.
The money saved doing that could enable you to buy a few other large shrubs of varying heights to plant around it, in the process creating your own varied mini woodland copse.
Betula utilis var. jacquemontii (Himalayan birch)