“Tree planting will make the rest of your life feel easier.” (summitplanting.com)

Where I planted, The ground was often rocky so it was tricky to close the holes properly after planting a tree. It's also very important not to bend the tree roots. It would be very difficult to accomplish that reliably without bending over. As far as specialized tools, generally from what I have seen the spade is sharpened and one half is usually ground completely off