Those trees that develop multiple trunks can be some of the most interesting visually. While a single strong leader is everyone's idea of a typical tree form, in natural and unmanaged woods we're more likely to come across diverse and 'non-standard' forms. Some of us think this has more character and interest.
It's intriguing in each case to speculate how this 'natural coppicing' has occurred. It may be that the very young tree has been nibbled by some species of wildlife or even damaged in a fire. Clever detective work may reveal some clues.
This multiple trunking is particularly common in Rowan and far less so in Pine or Oak.