While small branches might be broken by hand or braced perhaps against you knee, there comes a point where extra effort for stubborn or larger pieces is needed. Leverage is the key and a double trunk provides the means.

In a more domestic application, bent metal rods or pipes can be straightened. Years ago I did maintenance work at some apartments and occasionally a tenant would back into a chain link fence and bend the top pipe rail. I would remove it and use a double trunk tree on the premises to straighten it out before replacing it.

You may find multiple tree trunks instead of doubles that would be suitable and in some cases narrow “Y” shaped branches, but tree trunks are the strongest and doubles are the most efficient.