You can select one of the following tree layouts:

To do it press the Layout toolbar button and check the required item in the appeared menu or select it in the Tree settings Options Panel tab: 

<center>
     <br>
     <img src="/wiki/download/attachments/4227573/Selecting Tree Layout_0.png"/>
     <br>
</center>

See the example of the Circular layout:

<center>
     <br>
     <img src="/wiki/download/attachments/4227573/Selecting Tree Layout.png"/>
     <br>
</center>

Also you can select one of the following tree view: