def run_deltree(delitems, nexus_obj, log):
    """
    Returns a list of trees to be deleted

    :param deltree: A string of trees to be deleted.
    :type deltree: String

    :param nexus_obj: A `NexusReader` instance
    :type nexus_obj: NexusReader

    :return: A NexusReader instance with the given trees removed.
    """
    new = []
    log.info('Deleting: %d trees' % len(delitems))
    for index, tree in enumerate(nexus_obj.trees, 1):
        if index in delitems:
            log.info('Deleting tree %d' % index)
        else:
            new.append(tree)
    nexus_obj.trees.trees = new
    return nexus_obj
