\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}
  [,phantom,before drawing tree={x=0pt},for tree={concept,edge={-Stealth}}
    [{\name{AosOpenLeftTraits\_2}},name=olt
      [\name{AosOpenBoundaryTraits\_2},name=oyt,before drawing tree={x=0pt}]
    ]
    [{\name{AosOpenRightTraits\_2}},name=ort]
    [{\name{AosOpenBottomTraits\_2}},name=obt]
    [{\name{AosOpenTopTraits\_2}},name=ott]
  ]
  \draw[-Stealth] (ort) to (oyt);
  \draw[-Stealth] (obt) to (oyt);
  \draw[-Stealth] (ott) to (oyt);
\end{forest}
\end{document}
