How to show a hierarchical terms list?

<ul>
    <?php $hiterms = get_terms("prod_cat", array("orderby" => "count", "parent" => 0, "hide_empty" => 0)); ?>
    <?php foreach($hiterms as $key => $hiterm) : ?>
        <li>
            <?php echo $hiterm->name; ?>
            <?php $loterms = get_terms("prod_cat", array("orderby" => "slug", "parent" => $hiterm->term_id, "hide_empty" => 0)); ?>
            <?php if($loterms) : ?>
                <ul>
                    <?php foreach($loterms as $key => $loterm) : ?>
                        <li> - <?php echo $loterm->name; ?></li>
                    <?php endforeach; ?>
                </ul>
            <?php endif; ?>
        </li>
    <?php endforeach; ?>
</ul>