class NestedTreeRepository extends Gedmo\Tree\Entity\Repository\NestedTreeRepository
{

    public function findTreeByRootId($id)
    {
        // unefectively retrieves all the entities in tree
        // fuck it for now, better that query for each entity
        $this->createQueryBuilder('n')
                ->select('n', 'ch')
                ->leftJoin('n.children', 'ch')
                ->where('n.nodeRoot = :id')
                ->setParameter('id', $id)
                ->getQuery()->getResult();

        // returns already managed entity
        return $this->find($id);
    }

}