print entire tree onto poster size , how to?

I would like to print a poster size print of my entire tree , when i went into a fed ex store to do this , I sent them a email of my tree but they could not do it , because the way of the site is set up , do i need to be a full paid pro member to do this ?they could not enlarge it , every time they tried it was not ledgeable , is there any way to do this ?