protected function _deleteFromTree($entity) {
		extract($this->_config);

		$span = 1;
		if ($entity->$right - $entity->$left !== 1) {
			$span = $entity->$right - $entity->$left;
			$model::remove([$parent => $entity->data($model::key())]);
		}
		$this->_update($entity->$right, '-', $span + 1, $this->_scope($entity));
		return true;
	}