\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{AosBasicTraits\_2},name=abt,before drawing tree={x=0pt},for tree={concept,edge={-Stealth}}
      [\name{AosVerticalSideTraits\_2}
        [\name{AosLeftSideTraits\_2}
          [,phantom]
          [\name{AosIdentifiedVerticalTraits\_2},name=ivt
            [,phantom]
            [\name{AosSphericalBoundaryTraits\_2},name=sbt,before drawing tree={x=0pt}]
          ]
        ]
        [\name{AosRightSideTraits\_2},name=rst]
      ]
      [\name{AosHorizontalSideTraits\_2},before drawing tree={x-=1.5em}
        [\name{AosBottomSideTraits\_2}
          [\name{AosContractedBottomTraits\_2},name=cbt,before drawing tree={x-=3em}]
        ]
        [\name{AosTopSideTraits\_2},before drawing tree={x-=3em}
          [\name{AosContractedTopTraits\_2},name=ctt,before drawing tree={x-=3em}]
        ]
      ]
    ]
    \draw[-Stealth] (cbt) to (sbt);
    \draw[-Stealth] (ctt) to (sbt);
    \draw[-Stealth] (rst) to (ivt);
  \end{forest}
\end{document}
