The panel and tree have not 'toolbar' property, but the user can get more flexible layout by applying 'layout' component to it. The code below shows how to add a toolbar to panel.
<div class="easyui-panel" title="Basic Panel" style="width:500px;height:200px;">
<div class="easyui-layout" fit="true">
<div region="north" border="false" style="padding:3px 5px;background:#efefef;">
<a href="#" class="easyui-linkbutton">Open</a>
<a href="#" class="easyui-linkbutton">Close</a>
</div>
<div region="center" border="false" style="padding:20px">
panel content.
</div>
</div>
</div>