\documentclass[12pt]{standalone}
\input{header}
\usepackage[edges]{forest}
\usetikzlibrary{shadows.blur,arrows.meta}
\pagestyle{empty}
\def\name#1{\textsf{\it #1}}
\tikzset{concept/.style={rectangle split,rectangle split parts=1,draw,
    fill=white,blur shadow,rounded corners,align=center}}
\begin{document}
\begin{forest}
    [\name{AosLeftSideTraits\_2},before drawing tree={x=0pt},
      for tree={concept,edge={-Stealth}}
      [{\name{AosOpenLeftTraits\_2}}]
      [{\name{AosClosedLeftTraits\_2}}]
      [{\name{AosContractedLeftTraits\_2}}]
      [{\name{AosIdentifiedLeftTraits\_2}}]
    ]
\end{forest}
\end{document}
