hierachical category list with description

<?php
process_cat_trees();

function process_cat_trees( $cat='' ) {/*****************************************************************
*
* alchymyth 2011
* transformationpowertools.com/wordpress
* a hierarchical list of all categories, with linked post titles
*
******************************************************************/

   if($cat == '') :
     foreach( get_categories('hide_empty=false') as $category ) :
     if( !$cat->parent ) { $next[] = $category; }
     endforeach;
   else:
     $next = get_categories('hide_empty=false&parent=' . $cat);
   endif;

 if( $next ) :
 foreach( $next as $cat ) :

 if(get_category($cat)->category_description) {
   $desc = '<span class="description">' . get_category($cat)->category_description . '</span>'; echo "\n"; }
  else { $desc = '<span class="description">no description available</span>'; }

 echo '<ul><li><a href="' . get_category_link($cat->term_id) . '">' . $cat->name . ' ' . $desc . '</a></li>'; echo "\n";
 process_cat_trees( $cat->term_id );
 endforeach;
 endif;

 echo '</ul>'; echo "\n";
}
?>