To add breadcrumbs to your bbPress forums for better navigation and SEO, use the following PHP code snippet:

<?php
function bbpress_breadcrumbs() {
    if ( function_exists( 'yoast_breadcrumb' ) ) {
        yoast_breadcrumb( '<p id="breadcrumbs">', '</p>' );
    }
}
add_action( 'bbp_template_before_forums', 'bbpress_breadcrumbs' );
?>

This code will display Yoast SEO breadcrumbs on your bbPress forum pages, improving user experience and search engine optimization.