Displaying all Blog, group categories & forums in a YUI tree

[Alfa1]

Im working on a vbadvanced YUI navigation tree. (which is inside a jquery harmonica)

<div id="tree3" class="yui-skin-sam">
<ul>
<li>Blog<ul>
<li>Cat 1</li>
<li>Cat 2</li>
<li>Cat 3</li>
<li>Cat 4</li></ul></li>
</ul>
</div>
<div id="tree4" class="yui-skin-sam">
<ul>
<li>Social Groups<ul>
<li>Cat 1</li>
<li>Cat 2</li>
<li>Cat 3</li>
<li>Cat 4</li></ul></li>
</ul>
</div>
<div id="tree5" class="yui-skin-sam">
<ul>
<li>Forum<ul>
<li>Forum 1</li>
<li>Forum 2</li>
<li>Forum 3</li>
<li>Forum 4</li></ul></li>
</ul>
</div>

How do I display lists of all Blog, group categories and forums in these trees?
How do I cache it so that it doesn't search for the information every time someone opens the page?