Original Tree:
$HASH1 = {
           Branch2 => {
                        Branch3 => {
                                     Branch4 => { Leaves => [ 'Leaf6' ] },
                                     Leaves  => [
                                                  'Leaf4',
                                                  'Leaf5'
                                                ]
                                   },
                        Leaves  => [ 'Leaf3' ]
                      },
           Branch5 => {
                        Branch6 => { Leaves => [
                                     'Leaf8',
                                     'Leaf9'
                                   ] },
                        Leaves  => [ 'Leaf7' ]
                      },
           Leaves  => [
                        'Leaf1',
                        'Leaf2'
                      ]
         };
New Tree:
$HASH1 = {
           Branch2 => { Branch3 => { Leaves => [
                        'Leaf4',
                        'Leaf5'
                      ] } },
           Branch5 => { Branch6 => { Leaves => [
                        'Leaf8',
                        'Leaf9'
                      ] } },
           Leaves  => [
                        'Leaf1',
                        'Leaf2',
                        'Leaf6',
                        'Leaf3',
                        'Leaf7'
                      ]
         };