Veja app 35

Inclui 99 nós no TreeView

    'Private Sub btnPopular_Click(sender As Object, e As EventArgs) Handles btnPopular.Click
    ' Dim a As Integer
    ' For a = 0 To 99
    ' TreeView1.Nodes.Add(CStr(a))
    ' Next
    'End Sub

Inclui 10 nós no nó do TreeView selecionado

    'Private Sub btnIncluirNo_Click(sender As Object, e As EventArgs) Handles btnIncluirNo.Click
    ' Dim a
    ' For a = 0 To 9
    ' TreeView1.SelectedNode.Nodes.Add(CStr(a))
    ' Next
    'End Sub

Remove o nó selecionado do TreeView

    'Private Sub btnRemoverNo_Click(sender As Object, e As EventArgs) Handles btnRemoverNo.Click
    ' TreeView1.SelectedNode.Nodes.Remove(TreeView1.SelectedNode)
    'End Sub