\tikzset{pics/folder/.style={code={%
    \node[inner sep=0pt, minimum size=#1](-foldericon){};
    \node[folder style, inner sep=0pt, minimum width=0.3*#1, minimum height=0.6*#1, above right, xshift=0.05*#1] at (-foldericon.west){};
    \node[folder style, inner sep=0pt, minimum size=#1] at (-foldericon.center){};}
    },
    pics/folder/.default={20pt},
    folder style/.style={draw=foldercolor!80!black,top color=foldercolor!40,bottom color=foldercolor}
}

\forestset{is file/.style={edge path'/.expanded={%
        ([xshift=\forestregister{folder indent}]!u.parent anchor) |- (.child anchor)},
        inner sep=1pt},
    this folder size/.style={edge path'/.expanded={%
        ([xshift=\forestregister{folder indent}]!u.parent anchor) |- (.child anchor) pic[solid]{folder=#1}}, inner ysep=0.3*#1},
    folder tree indent/.style={before computing xy={l=#1}},
    folder icons/.style={folder, this folder size=#1, folder tree indent=2*#1, inner xsep=10pt},
    folder icons/.default={11pt},
}


  \begin{forest}
    for tree={font=\sffamily, grow'=0,
    folder indent=.7em, folder icons}
    [dataset
      [metadata%, this folder size=20pt
          [children.csv, is file]
          [recordings.csv, is file]
          [annotations.csv, is file]]
      [recordings
          [raw
            [recording1.wav, is file]
%            [recording2.wav, is file]
            ]
          [converted
            [standard]
                [recording1.wav, is file]
%                [recording2.wav, is file]
            [vetted]
                [recording1.wav, is file]
%                [recording2.wav, is file]
          ]
        ]
      [annotations
        [its
            [raw
                [recording1.its, is file]
%                [recording2.its, is file]
            ]
            [converted,
                [recording1\_0\_0.csv, is file]
%                [recording2\_0\_0.csv, is file]
            ]
        ]
      ]
    ]
  \end{forest}