How to remove default form tag while rendering output in hook_theme

I am customizing the login form. I have to put all the three forms(login, register, forgotpassword) into one page.
I don’t want that unwanted root form tag, how can i remove that one? I am using drupal 7. This is my code.

template.php

function bartik_theme() {

$items = array();

$items['user_login'] = array(
    'render element' => 'div',
    'arguments' => array('form' => NULL),
    'variables' => array('form' => NULL),
    'path' => drupal_get_path('theme', 'bartik') . '/templates',
    'template' => 'user-login',
    'preprocess functions' => array(
          'bartik_preprocess_user_login'
    ),

);

return $items;

}

user-login.tpl.php

        <div id="signupbox">
            <?php
                $login_form = drupal_get_form ( 'user_login_block' );
                echo drupal_render ( $login_form );

                $forgot_password_form = drupal_get_form ( 'user_pass' );
                echo drupal_render ( $forgot_password_form );

                $register_form = drupal_get_form ( 'user_register_form' );
                echo drupal_render ( $register_form );
            ?>
        </div>

My problem is that all the 3 forms are rendering in one more form tag.

My Output:

<form action=”/drupal728/user” method=”post” id=”user-login”>

 <form>Login</form>
 <form>Password....</form>
 <form>Registration....</form>

</form>

I don’t want that unwanted root form tag, how can i remove that one? I am using drupal 7.