Ah, don't worry. If you just append to one side always and do an anti-balancing one, you get a string of lights.

  o  
   \  
    o  
     \  
      o  
       \  
        o  
         \  
          o  
           \  
            o  
             \  
              o  
               \  
                o

Hey we have the same tree!

    (()(()((())((())(()())))))

Pinus newickii

Mine looks weird but it's decorated:

    @star
    @lights
    @balls
    def christmas_tree():
        n1 = Node()
        n2 = Node()
        n3 = Node()
        n4 = Node()
        n5 = Node()
        n6 = Node()
        n7 = Node()
        n8  = Node(n1, None)
        n9  = Node(n2, n3)
        n10 = Node(n4, n5)
        n11 = Node(n8, n9)
        n12 = Node(n6, n7)
        n13 = Node(None, n11)
        n14 = Node(None, n12)
        return Node(n13, n14)

    christmas_tree()