\documentclass{standalone}
\usepackage{binarytree}
\usetikzlibrary{external}
\tikzexternalize
\tikzexternaldisable

\begin{document}
\btreesetexternal{%
  use automatic file name,%
  mode=list and make}
\btreeset{%
  top padding=0pt,%
  left padding=0pt,%
  right padding=0pt,%
  bottom padding=0pt,%
  external=false,separate=true,%
  label on every edge,%
  left label anchor=center,%
  right label anchor=center,%
  continue after turn=false,%
  continue at path end=false,%
  level distance scales=false,%
  sibling distance scales=false,%
  scale=0.7}

\BinaryTree{lrr:x,llrr:x,rll:x,rrll:x}{5}%
\BinaryTree{lrr:x,llrr:x,rll:x,rrll:x}{5}
\end{document}

.
