How to include stack trace in log but not in email

I want stack trace included in logs I write to file but not in emails sent to alert me to problems (it is not a good security practice). How do I do that? This is what I have:

defined('YII_TRACE_LEVEL') or define('YII_TRACE_LEVEL',3);

'log'=>array(
  'class'=>'CLogRouter',
  'routes'=>array(
    array(
      'class'=>'CFileLogRoute',
      'levels'=> '', //, info, error, warning', // empty means all levels = default
      'categories'=>'',//'application',// system.*', // default = empty = all categories
      'logFile'=>'trace.log',
    ),
    array(
        'sentFrom' => 'user@example.com',
        'class'=>'CEmailLogRoute',
        'levels'=>'error, warning',
        'emails'=>'user@example.com',
    )
  )
)