Here is the code:

 <table width="100%" cellpadding="0" cellspacing="10">
 <tr>
 <td width="20%">
 <rich:panel id="orgTreePanel">
 <rich:tree switchType="ajax" reRender="orgTreePanel" style="width:300px" value="#{rootOrganizationNode}" var="item" nodeFace="org">
 <rich:treeNode type="org">
 <h:outputText value="#{item.title}"/>
 <a4j:commandButton type="submit" value=">" reRender="formPanel" action="#{orgmanager.renderOrgForm(item.id)}"/>
 </rich:treeNode>
 </rich:tree>

 </rich:panel>
 </td>
 <td align="right">
 <a4j:outputPanel id="formPanel" ajaxRendered="true">
 <a4j:include viewId="#{orgmanager.form}"/>
 </a4j:outputPanel>
 </td>
 </tr>
 </table>

Buttons of each node show the form in formPanel correctly. But when expanding/collapsing nodes of tree, the content of formPanel disappears. I don't understand how an ajax call can change other parts of the page.