\documentclass{article}

\usepackage{pstricks,pst-node,pst-tree,rotating}
\pagestyle{empty}

\begin{document}
\begin{center}
\pstree[levelsep=6mm, treesep=6mm]{\Tc*{2pt}}{
\pstree{\Tc*{2pt}}{
\Tn
\Tn
}
\pstree{\Tc*{2pt}}{
\Tn
\Tn
}
}
\end{center}
\end{document}
