Multi-Trunk Birch in Pot: Separate or Plant Together?

A young birch with three trunks in a large pot—can they be separated and planted individually?

Check Root System

• If grown from seed: possibly three distinct trees—gently separate roots and plant individually.
• If a single seedling that branched: it's one root system. Cutting apart risks killing all.

Alternative

Plant the clump as-is. After a year, select the best trunk and remove the others at ground level.